用所给词的适当形式填空小题1:My sister

用所给词的适当形式填空
小题1:My sister ________(write) three English e-mails since last week.
小题2:We went to the bookstore ____________(buy) books yesterday.
小题3:I think it must be an ________________ (enjoy) job.
小题4:I will tell you when he _________(come) back tomorrow.
小题5:Brian walked on the street alone. Then he said to _________ (he):“I am lost”.