力的作用效果与哪些因素有关呢?为了探究这个问题,如图所示的是小明设计实验的几个主要步骤.用一个弹性较好的钢片固定在桌边,在钢片上用细线挂钩码(小明使用的钩码规格相同).
- I bought Collecting the Morning Flowers in the Evening, a book written by Lu Xun. Would you like to read __________?
- No, thanks. I have already bought __________.
甲图所示为测定空气中氧气含量的装置及药品。