下列不属于生物多样性的是（）
A.遗传多样性
B.物种多样性
C.物质多样性
D.生态系统多样性
参考答案：C
-The old man living in the opposite street passed away.
-_________? I saw him yesterday. [ ]
A. How about
B. What about
C. How come
D. What so
卷烟包生产车间夏季空气温度应保持在（）℃。
A.21±2
B.22±5
C.24±2
D.28±2
