题目内容：

can you tell me which one ----------(to buy/buying)

优质解答

to buy
疑问词 + 不定式 在此作tell的宾语.

追问：

it is time for us to take our dog for--------- walk. A.a B.an C.the D./ 拜托了

追答：

答案：A

追问：

i don't know what i will do this coming sunday . 保持句愿意 拜托了

追答：

I don't know what to do this coming Sunday.