Tea _______ by accident about 5000 years ago.
invented
was invented
is invented
We should protect the earth, we will have no water to drink.
—Why are you standing there,Kangkang?—I can’t see the blackboard clearly.Two tall boys are sitting me.
— are you going to Shanghai?—I’m taking the plane.
—Which is the biggest number of the four?— .
What did Mr.Smith do before he came to China?—He in a car factory.