I’d like to travel by air _________ it usually costs a lot of money.
| A．so | B．though | C．until | D．or |
We all know that paper burns in _________ .
| A．CO2 | B．N2 | C． O2 | D．CO |
This is one of the best films _________ this year.
| A．have been shown |
| B．that have shown |
| C．that have been shown |
| D．which has been shown |
________ our journey by camel was!
| A．What an exciting experience |
| B．What exciting experience |
| C．How excited experience |
| D．What an excited experience |
--- I don’t mind telling you what I know.
--- You _______. I’m not asking you for it.
| A．may not | B．can’t | C．don’t have to | D．mustn’t |
About _______ of the books in our school library are written in Chinese.
| A．four-fifth | B．four-fifths |
| C．fourth-fifths | D．fourths-fifth |