具有清肺化痰、软坚散结功效的止咳药是（）。
A.海藻
B.海蛤壳
C.海螵蛸
D.半夏
E.昆布
参考答案：B
The sun is shining . You'd better wear sunglasses while you are out.
A. brightly B. lightly C. heavily
知觉的四个基本特征是选择性、理解性、整体性和_________。
