experiment took as five months and turned out         great success. 

A．The; 不填       B．不填; a     C．The ;a      D．The; the

—Have you heard of this new brand of computer, Mike?

—Yes, of course and I’ve decided to buy         .

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

Our opinions on language learning differ greatly         each other’s in that respect. 

A．at      B．by     C．for    D．from

Bicycles have been around in our life for more than hundreds of years, but no one knows who __________the first bicycle. 

A．invented           B．had invented            C．has invented            D．would invent

Advertisements are powerful and some companies try to mislead us, so we         be careful when reading them.

A．can          B．may          C．must        D．would

Last Sunday, my cousin sent me an e-mail         me to his birthday party.

A．invited             B．inviting            C．to invite           D．having invited

High-speed trains travel at 300 kilometers an hour, which is about         normal trains.

A．four times the speed as                                B．the speed four times of

C．four times as the speed of                        D．four times the speed of

In a foreign company, if you have a good command of English, you         much more easily.

A．will promote                                               B．promote

C．will get promoted                            D．are promoted

China has planned to build the world’s largest national park,         is expected to replace America’s Yellowstone National Park. 

A．which       B．where       C．what     D．as

It’s Saturday afternoon and Tom together with two of his classmates         new tricks on the skating ramp.

A．has tried   B．have tried  C．is trying    D．are trying