具有清热解毒、利咽、消肿功效的药物是（）。
A.山豆根
B.马勃
C.牛蒡子
D.薄荷
E.射干
参考答案：A
在波速一定的条件下，频率越高，则波长越______．
Tom never _____ fun at home. [ ]
A. have much
B. has any
C. have any
D. has many
