________ your report, what is most important to protect our environment ?
| A．As a result of | B．Because of | C．With the help of | D．According to |
_______ 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 |
They lost their way in the forest, and _______ made matters worse was that night began to fall.
| A．it | B．which |
| C．that | D．what |