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
