All Paul’s money had been ________,so he had to make a living by begging.

That hero who died in the war was so brave that he never _____ to the enemies until death.

Obviously, the advantage we take of solar energy is ________   enough.We have to work still harder.

When in trouble，remember to stay calm，and everything will     well．

We can't _____ one to change the habits of a lifetime in a short time.