---How long did it _____ you to work out the difficult maths problems?
---I ______ about half an hour on it .
| A．take ; took | B．spend ; took | C．spend ; cost | D．take ; spent |
______ he is in trouble, his best friend always helps me.
| A．Whenever | B．Whatever | C．however | D．Never |
The plane was late, _________ we has to wait for half an hour.
| A．because | B．or | C．so | D．but |
Tony never spends money on traveling____ he likes staying at home.
| A．but | B．because | C．though | D．until |
________ is not an easy thing for everyone to master a foreign language.
A. That B. This C. It
The problem must be __________ discovered next time.
A. farther B.far C.further