钻进过程中,钻头成本曲线回升后,继续钻进时不经济。()
参考答案:对
As long as we persist in spreading scientific knowledge among the masses, all the strange beliefs are ________ to go out of our life.[ ]
A.necessary
B.important
C.difficult
D.bound
下列哪组是均能清热解毒,息风止痉的药物()
A.桑叶、薄荷
B.柴胡、葛根
C.牛黄、熊胆
D.荆芥、防风
E.紫花地丁、野菊花