1He _____（leave） when I came in .2 While he was in beijing ,he ____（call）on us every month.3I ____(not hear)from him since he lived in shanghai

1 was going to leave
2 called
3 Not having heard

1.was to(我进去时他正要离开)
2.called（乍看While he was in beijing ，好像后面用过去进行时，但是every month 表频率，又发生在过去，所以用一般过去式）
3.haven't heared（从过去的某个时间起一直到现在，用现在完成时）

1. had left
2. called
3. i have not heard( I haven't heard)
应该是这样了，恩恩~
希望能帮到你~

1. has left
2. called
3. have't heard

1.was,leaving
2.called
3.haven't ,heard