It is the test system, _______ the teachers, that is to blame for the heavy burden of middle school students nowadays.
If he_____his teacher' s advice, Asafa Powell would not be the fastest man in the world.
So suddenly _____ that the animals in the zoo looked very frightened during the total solar eclipse ( 日全食).
I wanted______cold meat but there was ______ left.
It is global warming, rather than other factors,_____ the extreme weather.
_____ the crisis of economy getting more and more serious, the government is searching for ways to improve people' s life.