The main cause of HIV / AIDS infection in China is drug abuse, ______ is very serious in Yunnan.
I was about to get on the bus ____someone called me from behind.
We won’t give up __________ we should fail 10 times.
Must I get through the business in one evening? No, you ________.
Let’s go to a movie after work, OK? — _____________
He sat at the desk, __________ a novel.