đang tải bài tập bài
{"segment":[{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":10,"ques":"Trong c\u00e1c hi\u1ec7n t\u01b0\u1ee3ng sau, hi\u1ec7n t\u01b0\u1ee3ng n\u00e0o l\u00e0 hi\u1ec7n t\u01b0\u1ee3ng h\u00f3a h\u1ecdc? ","select":["A. D\u00e2y s\u1eaft c\u1eaft nh\u1ecf th\u00e0nh t\u1eebng \u0111o\u1ea1n v\u00e0 t\u00e1n th\u00e0nh \u0111inh ","B. H\u00f2a tan thu\u1ed1c t\u00edm v\u00e0o n\u01b0\u1edbc ","C. C\u1ed3n \u0111\u1ec3 trong l\u1ecd kh\u00f4ng k\u00edn b\u1ecb bay h\u01a1i ","D. \u0110\u1ed1t c\u1ed3n trong kh\u00f4ng kh\u00ed thu \u0111\u01b0\u1ee3c h\u01a1i n\u01b0\u1edbc v\u00e0 kh\u00ed cacbon \u0111ioxit "],"hint":"","explain":"<span class='basic_left'>S\u1eaft ch\u1ec9 b\u1ecb bi\u1ebfn \u0111\u1ed5i h\u00ecnh d\u1ea1ng, kh\u00f4ng bi\u1ebfn \u0111\u1ed5i v\u1ec1 ch\u1ea5t<br\/>Thu\u1ed1c t\u00edm ch\u1ec9 h\u00f2a tan v\u00e0o n\u01b0\u1edbc, kh\u00f4ng b\u1ecb bi\u1ebfn \u0111\u1ed5i th\u00e0nh ch\u1ea5t kh\u00e1c<br\/>C\u1ed3n b\u1ecb bay h\u01a1i l\u00e0 hi\u1ec7n t\u01b0\u1ee3ng c\u1ed3n chuy\u1ec3n t\u1eeb th\u1ec3 l\u1ecfng sang h\u01a1i, kh\u00f4ng b\u1ecb bi\u1ebfn \u0111\u1ed5i v\u1ec1 ch\u1ea5t<br\/>C\u1ed3n \u0111\u00e3 chuy\u1ec3n h\u00f3a th\u00e0nh ch\u1ea5t kh\u00e1c l\u00e0 h\u01a1i n\u01b0\u1edbc v\u00e0 kh\u00ed cacbon \u0111ioxit<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":1}]}],"id_ques":2060},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":10,"ques":"Th\u1ed5i h\u01a1i v\u00e0o dung d\u1ecbch n\u01b0\u1edbc v\u00f4i trong ch\u1ee9a canxi hi\u0111roxit, th\u00ec tr\u00ean b\u1ec1 m\u1eb7t xu\u1ea5t hi\u1ec7n m\u1ed9t v\u00e1ng tr\u1eafng l\u00e0 canxi cacbonat. D\u1ea5u hi\u1ec7u \u0111\u1ec3 nh\u1eadn bi\u1ebft \u0111\u00e2y l\u00e0 hi\u1ec7n t\u01b0\u1ee3ng h\u00f3a h\u1ecdc l\u00e0 ","select":["A. C\u00f3 ch\u1ea5t m\u1edbi \u0111\u01b0\u1ee3c t\u1ea1o th\u00e0nh l\u00e0 canxi cacbonat ","B. H\u01a1i th\u1edf \u0111\u01b0\u1ee3c chuy\u1ec3n th\u00e0nh d\u1ea1ng l\u1ecfng ","C. H\u01a1i th\u1edf c\u00f3 ch\u1ee9a kh\u00ed cacbon \u0111ioxit ","D. T\u1ea5t c\u1ea3 c\u00e1c d\u1ea5u hi\u1ec7u tr\u00ean \u0111\u1ec1u sai "],"hint":"","explain":"<span class='basic_left'>Hi\u1ec7n t\u01b0\u1ee3ng ch\u1ea5t bi\u1ebfn \u0111\u1ed5i c\u00f3 t\u1ea1o ra ch\u1ea5t kh\u00e1c, \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 hi\u1ec7n t\u01b0\u1ee3ng h\u00f3a h\u1ecdc<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":1}]}],"id_ques":2061},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":10,"ques":"Bi\u1ebft r\u1eb1ng c\u1ed3n ch\u00e1y \u0111\u01b0\u1ee3c l\u00e0 c\u00f3 s\u1ef1 tham gia c\u1ee7a kh\u00ed oxi, t\u1ea1o ra n\u01b0\u1edbc v\u00e0 kh\u00ed cacbon \u0111ioxit. Ph\u01b0\u01a1ng tr\u00ecnh ch\u1eef c\u1ee7a ph\u1ea3n \u1ee9ng l\u00e0 ","select":["A. C\u1ed3n + n\u01b0\u1edbc $\\to $ kh\u00ed cacbon \u0111ioxit + kh\u00ed oxi. ","B. C\u1ed3n + kh\u00ed oxi $\\to $ kh\u00ed cacbon \u0111ioxit + n\u01b0\u1edbc. ","C. Kh\u00ed cacbon \u0111ioxit + n\u01b0\u1edbc $\\to $ C\u1ed3n + kh\u00ed oxi ","D. Kh\u00ed cacbon \u0111ioxit + c\u1ed3n $\\to $ kh\u00ed oxi + n\u01b0\u1edbc "],"hint":"","explain":"<span class='basic_left'><br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":1}]}],"id_ques":2062},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":10,"ques":"T\u1ea7ng ozon \u1edf ph\u00eda nam c\u1ef1c b\u1ecb th\u1ee7ng do ph\u1ea3n \u1ee9ng quang h\u00f3a. Ph\u1ea3n \u1ee9ng n\u00e0y x\u1ea3y ra khi ozon b\u1ecb ph\u00e2n h\u1ee7y th\u00e0nh oxi. S\u1ea3n ph\u1ea9m c\u1ee7a qu\u00e1 tr\u00ecnh quang h\u00f3a l\u00e0 ","select":["A. Hidro ","B. Ozon ","C. Oxi ","D. Nit\u01a1 "],"hint":"","explain":"<span class='basic_left'>Ph\u1ea3n \u1ee9ng h\u00f3a h\u1ecdc \u0111\u01b0\u1ee3c ghi theo quy t\u1eafc nh\u01b0 sau:<br\/>T\u00ean c\u00e1c ch\u1ea5t ph\u1ea3n \u1ee9ng $\\to $ T\u00ean c\u00e1c s\u1ea3n ph\u1ea9m<br\/>Ph\u1ea3n \u1ee9ng quang h\u00f3a l\u00e0: ozon $\\to $ oxi <br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":2063},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":10,"ques":"Nh\u1ecf dung d\u1ecbch bari clorua $BaC{{l}_{2}}$ v\u00e0o axit sunfuric ${{H}_{2}}S{{O}_{4}}$ th\u1ea5y c\u00f3 k\u1ebft t\u1ee7a tr\u1eafng l\u00e0 mu\u1ed1i bari sunfat $BaS{{O}_{4}}$ v\u00e0 axit m\u1edbi t\u1ea1o th\u00e0nh l\u00e0 axit clohidric $HCl$. C\u00f4ng th\u1ee9c v\u1ec1 kh\u1ed1i l\u01b0\u1ee3ng c\u1ee7a ph\u1ea3n \u1ee9ng h\u00f3a h\u1ecdc tr\u00ean l\u00e0 ","select":["A. ${{m}_{BaC{{l}_{2}}}}+{{m}_{BaS{{O}_{4}}}}={{m}_{{{H}_{2}}S{{O}_{4}}}}+{{m}_{HCl}}$ ","B. ${{m}_{BaC{{l}_{2}}}}+{{m}_{HCl}}={{m}_{{{H}_{2}}S{{O}_{4}}}}+{{m}_{BaS{{O}_{4}}}}$ ","C. ${{m}_{BaC{{l}_{2}}}}+{{m}_{{{H}_{2}}S{{O}_{4}}}}={{m}_{BaS{{O}_{4}}}}$ ","D. ${{m}_{BaC{{l}_{2}}}}+{{m}_{{{H}_{2}}S{{O}_{4}}}}={{m}_{BaS{{O}_{4}}}}+{{m}_{HCl}}$ "],"hint":"","explain":"<span class='basic_left'>Ph\u01b0\u01a1ng tr\u00ecnh ch\u1eef c\u1ee7a ph\u1ea3n \u1ee9ng l\u00e0<br\/>Bari clorua + axit sunfuric $\\to $ mu\u1ed1i bari sunfat + axit clohidric<br\/>\u00c1p d\u1ee5ng \u0111\u1ecbnh lu\u1eadt b\u1ea3o to\u00e0n kh\u1ed1i l\u01b0\u1ee3ng:<br\/>${{m}_{BaC{{l}_{2}}}}+{{m}_{{{H}_{2}}S{{O}_{4}}}}={{m}_{BaS{{O}_{4}}}}+{{m}_{HCl}}$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":1}]}],"id_ques":2064},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":10,"ques":"\u0110\u1ed1t ch\u00e1y 4,6 gam h\u1ed7n h\u1ee3p ${{C}_{3}}{{H}_{6}},{{C}_{2}}{{H}_{2}}$ trong kh\u00f4ng kh\u00ed thu \u0111\u01b0\u1ee3c 4,4 gam kh\u00ed cacbon \u0111ioxit $C{{O}_{2}}$ v\u00e0 1,8 gam n\u01b0\u1edbc. L\u01b0\u1ee3ng oxi c\u1ea7n thi\u1ebft trong kh\u00f4ng kh\u00ed \u0111\u1ec3 \u0111\u1ed1t ch\u00e1y ho\u00e0n to\u00e0n h\u1ed7n h\u1ee3p l\u00e0 ","select":["A. $2,6$ gam ","B. $1,6$ gam ","C. $3$ gam ","D. $3,2$ gam "],"hint":"","explain":"<span class='basic_left'>\u00c1p d\u1ee5ng \u0111\u1ecbnh lu\u1eadt b\u1ea3o to\u00e0n kh\u1ed1i l\u01b0\u1ee3ng:<br\/>$\\begin{aligned} & {{m}_{hh}}+{{m}_{{{O}_{2}}}}={{m}_{C{{O}_{2}}}}+{{m}_{{{H}_{2}}O}} \\\\ & \\to {{m}_{{{O}_{2}}}}=4,4+1,8-4,6=1,6g \\\\ \\end{aligned}$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":2}]}],"id_ques":2065},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":10,"ques":"Ta c\u00f3 th\u1ec3 \u0111i\u1ec1u ch\u1ebf kh\u00ed oxi b\u1eb1ng c\u00e1ch nung n\u00f3ng kali clorat $KCl{{O}_{3}}$. Nung 7 gam $KCl{{O}_{3}}$ c\u00f3 x\u00fac t\u00e1c thu \u0111\u01b0\u1ee3c 2,5 gam $KCl$ v\u00e0 2,4 gam kh\u00ed Oxi. Hi\u1ec7u su\u1ea5t c\u1ee7a ph\u1ea3n \u1ee9ng l\u00e0 ","select":["A. $70\\%$ ","B. $80\\%$ ","C. $75\\%$ ","D. $90\\%$ "],"hint":"","explain":"<span class='basic_left'>X\u00e9t t\u1ed5ng kh\u1ed1i l\u01b0\u1ee3ng c\u1ee7a s\u1ea3n ph\u1ea9m: <br\/>${{m}_{KCl}}+{{m}_{{{O}_{2}}}}=2,5+2,4=4,9\\ne {{m}_{KCl{{O}_{3}}}}$<br\/>Ch\u1ee9ng t\u1ecf l\u01b0\u1ee3ng kali clorat ch\u01b0a ph\u1ea3n \u1ee9ng h\u1ebft<br\/>Theo \u0111\u1ecbnh lu\u1eadt b\u1ea3o to\u00e0n kh\u1ed1i l\u01b0\u1ee3ng th\u00ec l\u01b0\u1ee3ng $KCl{{O}_{3}}$ ph\u1ea3n \u1ee9ng l\u00e0 4,9 gam<br\/>$\\to Hs=\\dfrac{4,9}{7}.100=70\\%$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":2066},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":10,"ques":"Cho s\u01a1 \u0111\u1ed3 c\u1ee7a ph\u1ea3n \u1ee9ng sau: $BaC{{l}_{2}}+AgN{{O}_{3}}--->AgCl+Ba{{(N{{O}_{3}})}_{2}}$. Ph\u01b0\u01a1ng tr\u00ecnh h\u00f3a h\u1ecdc c\u1ee7a ph\u1ea3n \u1ee9ng l\u00e0 ","select":["A. $BaC{{l}_{2}}+AgN{{O}_{3}}\\to AgCl+Ba{{(N{{O}_{3}})}_{2}}$ ","B. $BaC{{l}_{2}}+AgN{{O}_{3}}\\to 2AgCl+Ba{{(N{{O}_{3}})}_{2}}$ ","C. $BaC{{l}_{2}}+2AgN{{O}_{3}}\\to 2AgCl+Ba{{(N{{O}_{3}})}_{2}}$ ","D. $2BaC{{l}_{2}}+AgN{{O}_{3}}\\to AgCl+2Ba{{(N{{O}_{3}})}_{2}}$ "],"hint":"","explain":"<span class='basic_left'>B\u01b0\u1edbc 1: C\u00e2n b\u1eb1ng nh\u00f3m $N{{O}_{3}}$ \u1edf hai v\u1ebf c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh<br\/>Ta th\u1ea5y \u1edf v\u1ebf ph\u1ea3i c\u00f3 2 nh\u00f3m $N{{O}_{3}}$ c\u00f2n v\u1ebf tr\u00e1i c\u00f3 1 nh\u00f3m $N{{O}_{3}}$<br\/>$\\to $ Th\u00eam h\u1ec7 s\u1ed1 2 tr\u01b0\u1edbc ph\u00e2n t\u1eed $AgN{{O}_{3}}$<br\/>B\u01b0\u1edbc 2: C\u00e2n b\u1eb1ng nguy\u00ean t\u1eed $Cl$ \u1edf hai v\u1ebf c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh<br\/>Ta th\u1ea5y \u1edf v\u1ebf ph\u1ea3i c\u00f3 1 nguy\u00ean t\u1eed $Cl$ c\u00f2n v\u1ebf tr\u00e1i c\u00f3 2 nguy\u00ean t\u1eed $Cl$<br\/>$\\to $ Th\u00eam h\u1ec7 s\u1ed1 2 tr\u01b0\u1edbc ph\u00e2n t\u1eed $AgCl$<br\/> V\u1eady ta c\u00f3 ph\u01b0\u01a1ng tr\u00ecnh h\u00f3a h\u1ecdc l\u00e0 $BaC{{l}_{2}}+2AgN{{O}_{3}}\\to 2AgCl+Ba{{(N{{O}_{3}})}_{2}}$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":1}]}],"id_ques":2067},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":10,"ques":"Bi\u1ebft r\u1eb1ng kh\u00ed etilen ${{C}_{2}}{{H}_{4}}$ ch\u00e1y l\u00e0 x\u1ea3y ra ph\u1ea3n \u1ee9ng v\u1edbi v\u1edbi kh\u00ed oxi ${{O}_{2}}$, sinh ra kh\u00ed cacbon \u0111ioxit $C{{O}_{2}}$ v\u00e0 n\u01b0\u1edbc. T\u1ec9 l\u1ec7 t\u1eebng c\u1eb7p ch\u1ea5t trong ph\u01b0\u01a1ng tr\u00ecnh ph\u1ea3n \u1ee9ng n\u00e0o sau \u0111\u00e2y \u0111\u00fang ","select":["A. C\u1ee9 1 ph\u00e2n t\u1eed ${{C}_{2}}{{H}_{4}}$ t\u00e1c d\u1ee5ng v\u1edbi 3 ph\u00e2n t\u1eed ${{O}_{2}}$ ","B. C\u1ee9 1 ph\u00e2n t\u1eed ${{C}_{2}}{{H}_{4}}$ ph\u1ea3n \u1ee9ng t\u1ea1o ra 2 ph\u00e2n t\u1eed $C{{O}_{2}}$ ","C. C\u1ee9 1 ph\u00e2n t\u1eed ${{C}_{2}}{{H}_{4}}$ ph\u1ea3n \u1ee9ng t\u1ea1o ra 2 ph\u00e2n t\u1eed ${{H}_{2}}O$ ","D. T\u1ea5t c\u1ea3 c\u00e1c \u0111\u00e1p \u00e1n tr\u00ean \u0111\u1ec1u \u0111\u00fang "],"hint":"","explain":"<span class='basic_left'>Ta c\u00f3 s\u01a1 \u0111\u1ed3 ph\u1ea3n \u1ee9ng : ${{C}_{2}}{{H}_{4}}+{{O}_{2}}\\to C{{O}_{2}}+{{H}_{2}}O$<br\/>B\u01b0\u1edbc 1: C\u00e2n b\u1eb1ng nguy\u00ean t\u1eed cacbon tr\u01b0\u1edbc<br\/>V\u1ebf tr\u00e1i c\u00f3 2 nguy\u00ean t\u1eed $C$ c\u00f2n v\u1ebf ph\u1ea3i c\u00f3 1 nguy\u00ean t\u1eed $C$<br\/>$\\to $Th\u00eam h\u1ec7 s\u1ed1 2 tr\u01b0\u1edbc ph\u00e2n t\u1eed $C{{O}_{2}}$<br\/>B\u01b0\u1edbc 2: C\u00e2n b\u1eb1ng nguy\u00ean t\u1eed $H$<br\/>V\u1ebf tr\u00e1i c\u00f3 4 nguy\u00ean t\u1eed $H$ c\u00f2n v\u1ebf ph\u1ea3i c\u00f3 2 nguy\u00ean t\u1eed $H$<br\/>$\\to $Th\u00eam h\u1ec7 s\u1ed1 2 tr\u01b0\u1edbc ph\u00e2n t\u1eed ${{H}_{2}}O$<br\/>B\u01b0\u1edbc 3: C\u00e2n b\u1eb1ng s\u1ed1 nguy\u00ean t\u1eed $O$ <br\/>V\u1ebf tr\u00e1i c\u00f3 2 nguy\u00ean t\u1eed $O$ c\u00f2n v\u1ebf ph\u1ea3i c\u00f3 6 nguy\u00ean t\u1eed $O$<br\/>$\\to $Th\u00eam h\u1ec7 s\u1ed1 3 tr\u01b0\u1edbc ph\u00e2n t\u1eed ${{O}_{2}}$<br\/>V\u1eady ph\u01b0\u01a1ng tr\u00ecnh h\u00f3a h\u1ecdc l\u00e0 ${{C}_{2}}{{H}_{4}}+{3{O}_{2}}\\to 2C{{O}_{2}}+{{2H}_{2}}O$<br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":1}]}],"id_ques":2068},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":10,"ques":"C\u00f4ng th\u1ee9c h\u00f3a h\u1ecdc c\u00f2n thi\u1ebfu trong ph\u01b0\u01a1ng tr\u00ecnh h\u00f3a h\u1ecdc sau : $?+3AgN{{O}_{3}}\\to Al{{(N{{O}_{3}})}_{3}}+3Ag$ l\u00e0 ","select":["A. $Al$ ","B. $Ag$ ","C. $Cu$ ","D. $Zn$ "],"hint":"","explain":"<span class='basic_left'>Trong ph\u1ea3n \u1ee9ng h\u00f3a h\u1ecdc ch\u1ec9 c\u00f3 li\u00ean k\u1ebft gi\u1eefa c\u00e1c nguy\u00ean t\u1eed thay \u0111\u1ed5i l\u00e0m cho ph\u00e2n t\u1eed n\u00e0y bi\u1ebfn \u0111\u1ed5i th\u00e0nh ph\u00e2n t\u1eed kh\u00e1c<br\/>V\u1eady ch\u1ea5t c\u00f2n thi\u1ebfu \u1edf \u0111\u00e2y ph\u1ea3i l\u00e0 $Al$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":2069}],"lesson":{"save":0,"level":2}}

Điểm của bạn.

Câu hỏi này theo dạng chọn đáp án đúng, sau khi đọc xong câu hỏi, bạn bấm vào một trong số các đáp án mà chương trình đưa ra bên dưới, sau đó bấm vào nút gửi để kiểm tra đáp án và sẵn sàng chuyển sang câu hỏi kế tiếp

Trả lời đúng trong khoảng thời gian quy định bạn sẽ được + số điểm như sau:
Trong khoảng 1 phút đầu tiên + 5 điểm
Trong khoảng 1 phút -> 2 phút + 4 điểm
Trong khoảng 2 phút -> 3 phút + 3 điểm
Trong khoảng 3 phút -> 4 phút + 2 điểm
Trong khoảng 4 phút -> 5 phút + 1 điểm

Quá 5 phút: không được cộng điểm

Tổng thời gian làm mỗi câu (không giới hạn)

Điểm của bạn.

Bấm vào đây nếu phát hiện có lỗi hoặc muốn gửi góp ý