You never imagine what trouble I have _________thispaper in my house.

With the guide________the way, we finally got to the village which we were looking for. [ ]

John has put forward _______ most challenging question for us to answer.-Yes, it really is. I have never heard _______ harder one.

Did you telephone the manager’s office?—Yes，he__________back before 9 o’clock this morning.

tigers, although they have beentamed, can _____ attack their trainer.