进行免疫电泳时，抗体槽内加入 （）
A.人血清
B.抗人全血清
C.抗抗体（第二抗体）
D.补体
E.标记抗体
参考答案：B
Exciting as its special effects are ______, there is too much violence in the film.[ ]
A. to watch
B. to be watched
C. watching
D. being watched
（）是指投资者进行反向交易以了结所持有的合约。
A、认购
B、认沽
C、开仓
D、平仓
watched