the earth, Mars is too cold and Venus is fartoo hot _______ there to be any life.

The child doesn’t need any help. He is old enough to ______ himself.

_____he is ill, ____ he goes to school.

ou ever listened to the songYesterday once more, ________ singer died in her early years

Look! If we had begun to do the work yesterday morning, we _____ ourselves just like them．