选择填空（答案要告诉我为什么这样做）
①I _____ a letter to my good friend at 8:00 yestday evening.
A.wrote B.am writing C.was wrieing D.write
②The word "hour" has _____ "h" _____"u" and _____"r" in it
A.an,an,a B.a,an,an C.an,a,an D.a,an,a
③We _____ football when it began to rain.We had to stop and go home..
A.played B.were playing C.will play D.are going to play
④Look!_____ fine weather it is today!
A.What a B.What C.How a D.How
⑤---Hello,is that Mr.Green speaking?
-----Yes,_____?
A.who's that B.who is he C.who are you D.who is it
⑥I had _____ my homework before I went to bed.
A.to finished B.finishing C.to finishes D.to finish