The young man invited the lady to dance with him, but she ______ his invitation．

Before the war broke out, many people ______in safe places possessions they could not take with them.

Sam ______ some knowledge of the computer just by watching others working on it.

---Can you think of another good idea?---This is the best approach I can imagine ______ the work ahead of schedule.

I set out to ___________ Liu Ming.