I have already forgotten ______ you bought the computer.

I heard that some patients who had undergone laser eye surgery experienced sudden losses of vision, ______?

last decade, Chicago public schools ________teaching of Chinese to serve 12,000 students.

(2013·高考湖北卷)He didn’t selfishly keep for himself the money inherited from his uncle.Instead，he made a________contribution to help the community.

I like Britney Spears. She’s ________favorite singer.