物质的性质 物质的用途
小科模拟池塘生态系统制作了如图所示的生态球,将其置于光线良好的地方。
“古人学问无遗力,少壮工夫老始成。纸上得来终觉浅,绝知此事要躬行。”陆游的这首诗主要强调 ( )
In our school library there ____________ a number of books on science, and in these years the number of them ____________ growing larger and larger.