I think going swimming in my spare time, _____ I think is great fun and good exercise as well as a useful skill.

I’m fine — I just felt a bit sleepy and tired, that was ________ I went to bed so early."

 ___ we know some basic knowledge concerning AIDS, we can protect ourselves from being infected.

 Liao Fan, a Chinese actor, finally got to know     real success tastes like when he won the prize for Best Actor at the 64th Berlin film festival. 

I have worked with children, so I know _____ to expect in my job.