she has't seen his family___three years ago.中为什么填since而不填bef

she has't seen his family___three years ago.中为什么填since而不填bef she left shanghai two years ago ,保持句意.怎么填she has _ _from sha It is the worst weather since 50 years ago为什么不是It has been.不 Mary ____ ____in China since three years ago .填什么 It has been years since I returned home,为什么since用,而不用when?分不 Since then,it_______every 4 years.为什么填is held而不是has been hel I saw her five years ago,since when I haven't seen her 定语从句的 His attitude to me wasn‘t ___a comrade.画线处为什么要填that of而不填lik i hear that his father( )since 10 years ago.a.has died b.die He always helps other people _____.为什么填in his life而不填in his She has lived in Shanghai( since three years ago).(就划线部分提问) 现在完成时讲解1.She has worked since ten years ago.2.It is ten year