hat do you think of genetically modified food (转基因食品)? —We all think ______ is careless ______ some scientists to say it is safe before doing any experiment.

I think ____ of the materials I listened to at the beginning of the exam ____ easy.

He is too tired. He doesn’t want to do_______.

The computer is ______useful tool in _______world today.

Anna is outgoing.She has _______ friends.