As we all know, independence is very ________ for youngsters because sooner or later they will leave their families and live alone.
| A．essential | B．accurate | C．flexible | D．temporary |
_______ she couldn’t understand was ______ fewer and fewer students showed interest in her lessons.
| A．What; why | B．That; what |
| C．What; because | D．Why; that |
It is pretty well understood _______ controls the flow of carbon dioxide in and out the atmosphere today.
| A．that | B．when |
| C．what | D．how |
Country life gives him peace and quiet, which is ______ he can’t enjoy while living in big cities.
| A．that | B．why |
| C．where | D．what |
“What were you trying to prove to the police？” “___ I was last night.”
| A．That | B．When |
| C．Where | D．What |
It has come to my notice _______ some of you have missed classes.
| A．what | B．which |
| C．that | D．when |