Walt, feeling a bit tired, decided to stop off ______ in Hong Kong on the way to Singapore. 

He has called several times this morning; _____ there is something very important.

Young people spend most of their time _________, for they don’t want to stay at home all day.

You can’t go out because it is a stormy night;       , your homework hasn’t been done.

Much to my surprise, the eight-year-old boy       fixed my computer within ten minutes．