1The environment in major cities in our country has been improved ____ some extent in the last decade.

1The environment in major cities in our country has been improved ____ some extent in the last decade.
A.by B.to C.in D.with
2.My friend has returned from the UK.She ____ at Oxford for four years,during which we communicated with each other on the Internet.
A.studied B.has studied C.had studied D.has been studying
3We ____ estimate the spirit of the Shanghai Expo too much,which is sure to play an important role in our daily life.
A.may not B.should not C.must not D.cannot
4____ in the front row at the ceremony,our distinguished guests are from home and abroad.
A.Seating B.Being seated C.Seated D.To seat
5.I received a call from the police at midnight yesterday._____ that he had been badly injured in a car accident.
A.Then did I learn B.Only then I learned C.Only then did I learn D.Only then learned I
6— Will the plan ____ the libraries nationally be carried out in the coming year?
— It all depends,I suppose.
A.to promote B.promote C.promoting D.that promote