在“ 验证力的平行四边形定则”实验中，F 1 和F2 表示两个互成角度的力，F表示由平行四边形定则作出的F1和F2的合力，F´表示一个弹簧拉橡皮条时的力，则图中符合实验事实的是（ ）
答案：A
因为F表示由平行四边形定则作出的F1和F2的合力，则一定在平行四边形的对角线上，F´表示一个弹簧拉橡皮条时的力，则一定与橡皮条的伸长方向在一条直线上，故选A。
| 选择和画线部分单词或词语意义相近的选项。 |
| 1. We eat fast food for lunch at times. |
[ ] |
| A. all the time B. sometimes C. some times |
| 2. What a bright summer morning! |
[ ] |
| A. cloudy B. rainy C. sunny |
| 3. Mike didn't look happy after he saw his grandmother in hospital. |
[ ] |
| A. was sad B. was glad C. was sick |
| 4. At first, I didn't like singing but now I like it very much. |
[ ] |
| A. At times B. First C. At the beginning |
| 5. The old woman felt nervous as she tried to cross the busy road. |
[ ] |
| A. worry B. tense C. angry |