I was about to go to bed _____ one of my old classmates made a call to me.

The earthquake which happened in Yushu14th April 2010 was a big disaster. [ ]

What are people supposed to do when they meet ________the first time? —They are supposed to bow. [ ]

My father is able to _______many different kinds of computers.

The skirt looks different from others and it is nice.—Thanks. It ______ by my mother last month.