薄荷人煎剂宜 ① ；对 ② 者，不宜使用。
参考答案：①后下 ②体虚多汗
Find ways to praise your children often, ________ you'll find they will open their hearts to you.[ ]
A. till
B. or
C. and
D. but
渠道雷诺数如果用水力半径作为特征长度，则层流、紊流的临界雷诺数是（）。
A.500
B.1000
C.1500
D.2000
