ericans would prefer to keep their problems themselves,and solve their problems ______ themselves.

He failed to_________ himself to the new environment.[ ]

I can’t go with you. I _______stay at home until my parents come back.

We can’t be successful _____ we keep on working hard.—I agree with you.

填入下面一段文字横线处的语句，最恰当的一句是（ ）职责的转变与业务量的增加使得对消防员的要求也越来越高， 。新兵从一个地方青年到一个合格的消防战斗员，通过训练和实战需要半年到一年左右的时间。除了理论知识的学习，体能的训练，心理素质也是极为重要的一项课程。后期实战也会让新人真正深入到各种突发灾害中，让其心理素质和胆量在训练和实战中得到强化。