英语,过去完成时题目.

英语,过去完成时题目.
1.They ___________ (be) to the Beijing Zoo five times by the end of last term.
2.By the time he was ten,Edison __________ ( build) his own chemistry lab.
3.-Would you like to have an egg
- No,thanks.I _________ ( have ) one before you came here.
4.She ___________ (visit) Austrelia three times before she was twelve.
5.The house was dirty.They _______ ( not clean) it for weeks.
6.Yesterday morning I ________ (cal) to Mr.Wang,but nobody answered.
7.Last night Amy was really busy,she ___________ (help) to wash the dishes,___________ ( clean) the room and __________ (do ) her homework then went to bed.