Language is changing all the time. Some English words today can mean totally different things to _____ they meant before.
| A．which | B．that | C．不填 | D．what |
_______ we are doing has never been done before.
| A．That | B．What |
| C．Which | D．Whether |
_______ 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 |
“What were you trying to prove to the police？” “___ I was last night.”
| A．That | B．When |
| C．Where | D．What |
. Patience is a kind of quality — and that is ___A___ it takes to do anything well.
| A．what | B．which |
| C．which | D．how |