Why not look up the new word in the dictionary ________ you don't know it?

A．if

B．that

C．though

D．whether

I can't understand this sentence well ________ there are few new words in it．

A．but

B．because

C．so

D．although

You'll be late ________ you don't get up early tomorrow morning．

A．if

B．when

C．before

D．until

It's five years ________ I came to this town．

A．since

B．when

C．before

D．until

You'd better do it ________ your mother did．

A．when

B．as

C．like

D．because

Bob spends lots of money ________ he is not rich．

A．if

B．though

C．since

D．because

David didn't go to bed ________ he finished his homework．

A．until

B．after

C．while

D．when

－Hi, Mr Wang．

－I'm sorry, ________ I don't think I know you．

A．and

B．or

C．but

D．because

________ my mother ________ my sister watches TV these days．

A．Either, nor

B．Both, and

C．Neither, nor

D．Neither, or

I don't know ________ I can do it．

A．what

B．which

C．how

D．who