What do you think of his story in the forest? — , I can’t believe it.

We need clear air and water, so we _____ protect the environment.

Has your teacher returned from America yet? –Yes, but he _______ here for only three days before his company sent him to Africa

The great success of this programme has been ____ due to the support given by the local businessmen.

My parents showed some old pictures that brought back sweet memories.