从物质循环的观点看，生物体内碳元素的最终来源是[ ]
A．食物所含有机物中的碳
B．非生物界中的碳酸盐
C．大气中的二氧化碳
D．生态系统中的生产者
答案：C
用括号内所给词的适当形式填空。
1. Did you expect _____ (see) your father?
2. You can see the picture on the wall over _____ (people) heads.
3. Is it the band which gets everyone _____ (dance)?
4. His grandmother is famous as a _____(photograph).
5. Those drums are really _____ (loud).
表达式2*5/2．5，1．0/2*5，1/2．3和5/3的计算结果分别是【 】。
e picture on the wall over _____ (people) heads.
e drums are really _____ (loud).