_______ in her graduation paper, Mary has no time to do a part-time job.
| A．Having been burying | B．Having buried |
| C．To be buried | D．Buried |
Gun control is a subject ______ Americans have argued for a long time.
| A．of which | B． with which |
| C． about which | D．into which |
Whenever I met her, ______ was fairly often, she greeted me with a sweet smile.
| A．who | B．which |
| C．when | D．that |
It's helpful to put children in a situation ______ they can see themselves differently.
| A．that | B．when |
| C．which | D．where |
Mark drives his car too fast and, what's more, very carelessly, ________ worries his mother.
| A．a | B．what |
| C．it | D．which |
Occasions are quite rare ________ I have the time to spend a day with my kids.
| A．who | B．which |
| C．why | D．when |