问题
选择题
| I wasn't sure if he was really interested or if he _____ polite. |
A. was just being B. will just be C. had just been D. would just be |
答案
答案：A
搜题请搜索小程序“爱下问搜题”
| I wasn't sure if he was really interested or if he _____ polite. |
A. was just being B. will just be C. had just been D. would just be |
答案：A
如图所示是“探究滑动摩擦力的大小与哪些因素有关”的实验．
（1）实验中为了测量滑动摩擦力的大小，应用弹簧测力计沿水平方向 拉动木块；
实验数据如下：
| 序号 | 接触面 | 压力/N | 滑动摩擦力/N |
| 1 | 木块与木板 | 2.0 | 0.4 |
| 2 | 木块与木板 | 2.5 | 0.5 |
| 3 | 木块与砂纸 | 2.0 | 0.6 |
（3）在第一次实验中如果用0.5N的力水平拉动木块，则木块受到的滑动摩擦力为 N．