6.One kind of tool that was popular during the Stone Age was a flake, ________ cutting and scraping.

5.Like humans, these zoo animals must have a dentist ________ their teeth.

4.In partnership with John D. Rockefeller, Henry Flager ________ the Standard Oil Company.

Some people like drinking coffee, for it has ________ effects.

A．promoting

B．stimulating

C．enhancing

D．encouraging

Why! I have nothing to confess. ________ you want me

 to say?

A．What is it that

B．What it is that

C．How is it that

D．How it is that

Jasmine was holidaying with her family in a wildlife park ________she was bitten on the leg by a lion.

A．when

B．while

C．since

D．once

American women usually identify their best friend someone ________ they can talk frequently.

A．who

B．as

C．about which

D．with whom

The flowers ________sweet in the botanic garden attract the visitors to the beauty of nature.

A．to smell

B．smelling

C．smelt

D．to be smelt

He speaks English well indeed, but of course not ________a native speaker.

A．as fluent as

B．more fluent than

C．so fluently as

D．much fluently than

Bill's aim is to inform the viewers that cigarette ad- vertising on TV is illegal, ________ ?

A．isn't it

B．is it

C．isn't he

D．is he