.

In those days, the old woman __________ sit at the door for hours, waiting for her son to return from abroad.

A．should

B．used to

C．might

D．would

以下药液浸泡法中哪一项是错误的：

A．2%中性戊二醛水溶液

B．5%甲醛溶液

C．70%酒精

D．1:1000新洁尔灭溶液

E．1:1000洗必泰溶液