单选题 We should be(　　) of cultural differences while doing foreign trade.

单选题 It would be more (　　)to combine the two factories.

单选题 Birds learn to fly by (　　)

单选题 Employees would like to work under team leader who (　　)good examples.

单选题 We regret (　　)you that your VIP card has expired.

单选题 My mother bought a lot of food, but I haven't found anything (　　) I really want to eat.

单选题 My computer is too slow and I want to(　　)it

单选题 His father is able to (　　) the family back to many centuries ago 

单选题 You can't marry such a(n) (　　) man. He is a liar.