色素
参考答案：
生物体组成中的一种分子内具有较复杂共轭体系、多属杂环化合物聚合体的有色物质。
—Excuse me. Could you tell me _____?
—It will leave at 4:00 p.m. [ ]
A. how will you go to Shanghai
B. how you will go to Shanghai
C. when will the bus leave for Shanghai
D. when the bus will leave for Shanghai
轴流式风机的效率比一般离心式风机低。
