写作酒泉--第8、9、10瓢

We \' re often told that GM foods pose no  threat to human health . But is this really the case ?

We \' re often told that the earth is becoing warmer and warmer . But is this really the case ?

The use of  computer is a widespread methord for   midddle school  students ,but is  it a wise one ? the methord is now being challed by more and more  parents.