频繁操作的交流接触器,应每( )进行一次检查。
A.一个月
B.半年
C.三个月
D.一年
参考答案:C
--- I think Tom shouldn’t ask his mother for so much money.
--- I _____. It’s not easy for her to make money.
A.don’t agree
B.think
C.agree
D.don’t think so
B细胞抗原识别受体是()
A.TCR
B.CD3
C.FcR
D.CR2
E.Smlg