题干

I _______ this computer five years ago.

A:buy

B:bought

C:have bought

D:has bought

上一题 下一题 0.0难度 选择题 更新时间:2018-09-16 05:11:05

答案(点此获取答案解析)

B

同类题5

根据下表中烃的分子式排列规律,判断空格中烃的同分异构体数目是
1
2
3
4
5
6
7
8
CH4
C2H4
C3H8
C4H8
 
C6H12
C7H16
C8H16