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
The three backpackers finally reached the top of Mount Huangshan, ________ they could enjoy the breathtaking sights to their heart's content.
A．when B．where
C．why D．how
