The problem wasn’t difficult for him,was it ?-______. He should have been given a more difficult one.[ ]

jority of rural migrants are engaged in the most painstaking, most tiring and dangerous work, _______ college graduates are reluctant to do.

Jack is really a brave guy — So he is And we can’t admire his courage _____ [ ]

下列各句中，没有语病的一项是（ ）

eacher praised me for ________ progress I’d made, which was ________ great encouragement to me.