There is a big gap ________ the lives of the teenagers and adults now．

A．in

B．among

C．between

D．on

The trip to Thailand was ________ by World Vision．

A．pay

B．funded

C．taken

D．spent

She found that ________ was quite difficult in England．

A．saying

B．speaking

C．communicating

D．talk

Some problems always ________ me before I go to sleep．

A．troubled

B．hurt

C．frighten

D．worry

She gave a talk ________ Australia ________ some classes in school．

A．about; to

B．with; to

C．about; about

D．in; to

Joyce wanted to have some articles about ________ visits to ________ countries．

A．educate; other

B．educational; another

C．educating; the other

D．educational; other

We climbed ________ rock in the world and later we saw some kangaroos in Australia．

A．the bigger

B．the biggest

C．big

D．the big

Air pollution ________ from many ________ sources．

A．is coming; differ

B．is coming; difference

C．comes; different

D．comes; differences

I enjoy playing chess ________ it takes me a lot of time．

A．unless

B．because

C．when

D．though

I have explained everything ________ I can to tell you．

A．what

B．which

C．that

D．how