帮个忙用since,for,have gone,have been填1.We have learned five les

帮个忙用since,for,have gone,have been填1.We have learned five lessons__the beginning of this term.
2.Mrs Liao has been in hospital__last week.3.I have stayed at my aunt's___two weeks.4.Where are the boy students?They___to the library.5.Is your father in?No,he__to Shenzhen.___he ever ___there befor Yes,he___there several times.6.I want to go to Shanghai for a visit because I___never____to that city before.