Now the pollution caused by the increasing number of cars more and more serious in many cities
A.become
B.became
C.is becoming
D.had become

单项选择题We want to （）how animals use tools.

A.survey
B.investigate
C.research
D.inquiry

单项选择题The evidence was（）. We were convinced it was true.

A.irresistible
B.compelling
C.powerful
D.absorbing

单项选择题Those examples are not enough，you should give （）examples to make your argument convincing.

A.some
B.any
C.some more
D.any more

单项选择题–Excuse me, sir. I’m writing a research paper on Chinese culturA.Do you mind a few questions? --_____________B.CertainlyC.No, of course notD.By all meansE.Yes, please

单项选择题Which of the following statements gives the main idea of the second paragraph？（）

A.Credit cards are worse than currency.
B.Currency may not be more of a problem than credit cards.
C.We use credit cards because people steal money.
D.We have many problems with money.