--Was the driving pleasant when you vocationed in Mexico last summer?

----No, it ___ for four days when we arrived, so that the roads were very muddy.

A．was raining

B．had been raining

C．would be raining

D．have rained

小婴儿出现生理性流涎的年龄是()

A．9～10个月

B．7～8个月

C．5～6个月

D．3～4个月

E．1～2个月