电泳槽自配槽后就应连续循环,停止搅拌不应超过2h。
参考答案:错
I go _________ the washroom.[ ]
A. for
B. to
C. at
—What should I buy in the supermarket, Mom?
—You can buy you need to buy. [ ]
A. why
B. what
C. which
D. how