1She( to wonder) when he (to be back) from New Zealand.
2He (to be) to Canada before he (to visit) London?
3It (to be) three years Shannon (to try) to find a subject for research.
4 It was a very difficult task. I (to understand) it when I (to read) it several times.
5He( to leave) for Canada before his family moved to this city and (to live) there since then.
- As she (not to know)
what kind of present to give him, she (to ask) her friend for advice.
7What he (to do) when you (to call on) him?
8She (to have) that unknown disease since she (to be) 15 years old.
9 Yesterday when I (to walk) along the street I met a friend of mine whom I (not to see) for nearly ten years