30．---- Do you think it's a good idea to make friends with your students?---- _____ , I do. I think it's a great idea.

27．My uncle’s house in the downtown area is much smaller than ours , but it is twice _______ expensive . 

 --- How long ____ was this? --- It’s been nearly six years now.

--- How many subjects are you good at?--- Three, ______, English, Chinese and politics.

Flight attendants usually need to arrive at the airport ______ before their flight leaves.

33. The employees have not been paid _______ since the new manager took over this company last month.

The guide showed the travelers _____ of the factory.

---What can I do for you？---Well，I’m afraid the box is heavy for you，but thank you all the same．

The problem was that it is ___ valuable ___everyday use. 

Suan! Where have you been? You have no idea ___ worried I was !

When we sleep is      cultural as biological-and practices differ greatly round the globe.

He broke      a piece of chocolate and gave it to me before he broke the rest  into pieces.

 -Tom, why didn't you go to the flower show? -I think it's something _______ pleasant. 

He once worked out a plan for the project; ______, most people didn’t agree to it.

He was __ twenty when he was gone.

We haven’t heard from her for long, so we give her_____for dead.

Though she did not know Boston well, she made her way_____to the Home Circle Building.

—Where are the visitors from?—_______from South Africa.

The teacher always makes his class so ____and interesting for us.

Our English teacher has a _____ teaching method.