题目

The books here are not so well written as ___ on the shelf. A . that B . those C . ones D . them 答案：B正确的化学实验操作对实验结果、人身安全都非常重要．在下图所示实验操作中，正确的是（ ）A．闻气体气味B．移走蒸发皿C．倾倒液体D．将铁钉投入竖直的试管中