Here are the sentences with the verbs in brackets in the appropriate tense:
I (wonder) why she (not come) to the meeting.
While I (wait) for the bus, it (rain) heavily.
Look! A strange man (stand) outside the window and (stare) in.
The children (play) in the garden while their mother (cook) lunch.
We (discuss) our holiday plans at the moment but we (not/decide) where to go yet.
The weather (be) lovely today. The sun (shine) and it (feel) quite warm.