Although the old man is in his sixties, ___ he walks fairly fast.

What the boy enjoys _____ to have a room of his own.

— You look pale. Did you sleep well？— No. It was already midnight ____ I finished my homework.

. What the doctors really doubt is ______ my mother will recover from the serious disease soon.

He had just sent an e­mail to his pal on the Internet ________ the system broke down.