A. one of greatest inventor
B. one of the greatest inventors
C. one of greatest invention
D. one of the greatest inventions
[单选题]CH3(CH2)2CH2+(Ⅰ);CH3CH+CH2CH3(Ⅱ);(CH3)3C+(Ⅲ)三种碳正离子的稳定性顺序如何?()A . (Ⅰ)>(Ⅱ)>(Ⅲ);B . (Ⅰ)<(Ⅱ)<(Ⅲ);C . (Ⅱ)>(Ⅰ)>(Ⅲ);D . (Ⅱ)>(Ⅲ)>(Ⅰ)。
[判断题] 赖氨酸的结构式:CH2CH2CH2CH2CHCOOH。A . 正确B . 错误
[单选题]28.Mr Qin is_________A. Mr Smith's teacherB. Mrs Smith's teacherC. EnglishD. a teacher of English
[单选题]按照次序规则判断,-CH2OH、-CH2C(CH3)3、-CH2NH2的优先顺序为()。A . -CH2OH>-CH2NH2>-CH2C(CH3)3B . -CH2NH2>-CH2OH>-CH2C(CH3)3C . -CH2C(CH3)3>-CH2NH2>-CH2OHD . -CH2NH2>-CH2C(CH3)3>-CH2OH
[单选题]已知:CH3CH2CH2CH3(g)+O2(g)4CO2(g)+5H2O(l)ΔH=-2878kJ/mol;(CH3)2CHCH3(g)+O2(g)4CO2(g)+5H2O(l)△H=-2869kJ/mol;下列说法正确的是()。A . 正丁烷分子储存的能量大于异丁烷分子B . 正丁烷的稳定性大于异丁烷C . 异丁烷转化为正丁烷的过程是一个放热过程D . 异丁烷分子中的碳氢键比正丁烷的多
[单选题]24. The writer is_________ now.A. a businessmanB. also a teacherC. still a student
[单选题]3._________orange is_________ orange.A.A ;theB.An ;anC.An;/D./;an
[单选题]25. Peter’s sister is_________A. CindyB. GraceC.AliceD. Maria