A:生物多样性原理
B:整体性原理
C:系统整体性原理
D:协调与平衡原理
阳光在光井中经过多次____ 后,通过底部漫射器均匀高效地照射到需要光照的地方。
下列各组词语中,没有错别字的一组是 ( )
Last year, some groups of students in their community (社区) made a survey about "How do people spend their free time?" The following diagrams show some results of it:Diagram (1): Hours for people of different ages who surf the Internet in a week.Diagram (2): Different days people go to the library. (library attendance)Diagram (3): Different programs people like.根据上面三个图表内容,选择正确答案。