When I try to understand ________ that prevents so many children from being happy, there seem to be three causes.
| A．why it is | B．what it does | C．why it does | D．what it is |
I can __________ the house being untidy, but I hate it if it's not clean.
| A．come up with | B．put up with |
| C．turn to | D．stick to |
He decided that he would drive all the way home instead of __________ at a hotel for the night.
| A．putting down | B．putting off |
| C．putting on | D．putting up |
— Happy birthday!
—Thank you! It's the best present I __________ for.
| A．should have wished | B．must have wished |
| C．may have wished | D．could have wished |
Most American children go to state schools, but the private schools __________ be very good.
| A．must | B．can |
| C．should | D．ought to |
Since nobody gave him any help, he __________ have done the research on his own.
| A．can | B．must |
| C．would | D．need |