Only when all the fish in the lake died _____ how serious the pollution was.[ ]

The experiment show that proper amount of exercise, if ________ regularly, can improve our health [ ]

It remains to be seen ________ the newly formed committee’s policy can be put into practice

e get closer to the moon, we shall feel itsgravity pulling us, but it will not be ________ the earth’s.

Mr. Black must be worried about something. You can ____ it from the look on his face.[ ]