―Look! What a mistake! Why?

―Sorry, I _________ on it．

A．don’t concentrate                            B．hadn’t concentrated

C．haven’t been concentrating                    D．wasn’t concentrating

Barack Obama has taken personal blame ________ the security failures which led ________ the attempt to blow up a plane on Christmas Day．

A．of; to         B．for; to            C．on; on           D．in; on

This new kind of chemicals will help keep the air, soil and water________ from pollution．

A．free         B．empty         C．loose          D．short

If our car had not ________, we would have been here on time．

A．broken out              B．broken into              C．broken away           D．broken down

—It’s hard to believe that Jack ________ have fought with the policeman．

—Yes．If one ________ ask for trouble, it can’t be helped．

A．would; will          B．must; may        C．should; must        D．need; dare

Many of the creatures in the movie “Avatar” are not real, but much of __________ happens is attractive．

A．which           B．that         C．what          D．them

I would rather buy a house in the countryside than         in the city．

A．it           B．one          C．this           D．that

________, as long as I’m with nature, I don’t care．

A．However tough the voyage is

B．Whatever tough the journey is

C．However the voyage is tough

D．Whatever the journey is tough

______ happened to be no one in that house when the typhoon hit the area．

A．It          B．There               C．This         D．That

There are 51 students in Class Three, _____ failed in the test．

A．all of which               B．all of them              C．none of whom            D．none of them