The old town has small houses ________ are built close to each other．

A．they

B．where

C．what

D．that

Luckily, we'd brought a road map without ________ we would have lost our way．

A．it

B．that

C．which

D．this

It was on a lonely island ________ he was saved one month after the boat went down．

A．where

B．that

C．which

D．what

Jack wasn't saying anything, but the teacher smiled at him ________ he had done something very clever．

A．as if

B．even if

C．while

D．though

What shall we use for power when all the oil in the world has ________?

A．given out

B．put out

C．held up

D．used up

Advertisements have become part of our everyday life and so it is important that we ________ ourselves about them to protect us from being fooled by them．

A．must educate

B．might educate

C．could educate

D．educate

Television adverts are expensive to make and to show, so you have to be a big corporation with a big budget to ________ television ads．

A．reward

B．afford

C．award

D．record

It was not until the eighteenth and nineteenth centuries ________ the exploration of the botanical world began on a large scale．

A．where

B．when

C．that

D．how

What you said just now ________ me of that American professor．

A．remembered

B．informed

C．reminded

D．memorized

Only when we saw the photos about the celebration of Christmas in Yangzhou Daily ________ how splendid it was．

A．had we known

B．we had known

C．did we know

D．we know