为了保证转化催化剂还原质量,对微量()也要进行分析。
A、CO
B、CO2
C、S
D、H2
参考答案:C
我国反补贴调查,自立案调查决定公告之日起最长应该在( )内结束。
A.6个月
B.12个月
C.18个月
D.2年
Not only Tom but also Jack __________ to that city several times.[ ]
A. have been
B. has been
C. have gone
D. has gone