16. _______ medicine works in a human body is a question _______ not everyone can understand fully.
| A．How; that | B．That; which |
| C．That; which | D．What; that |
Recently quite a lot of experts _____ that another law on wildlife protection ____ as soon as possible.
| A．suggested; must be passed | B．have suggested; be passed |
| C．were suggesting; was passed | D．suggested; being passed |
— Why! I _____ get you on the phone.
— We ______ basketball on the playground when you phoned.
| A．didn't; must be playing |
| B．couldn't; must be playing |
| C．couldn't; must have played |
| D．didn't; must have been playing |
Often, when he ______ something that ______ him, he wasted his time drawing some little pictures.
| A．should be doing; gave |
| B．should have been doing; was given |
| C．should do; was given |
| D．should have been doing; had given |
Whatever your parents______ you 一there is real Santa Claus. And I should know, because I’ve seen him myself !
| A．may tell | B．could tell | C．may have told | D．must have told |
一Could you tell me what happed last night ?
一I can't go into detail now because it _______ take too long.
| A．would | B．should | C．might | D．could |