问题
选择题
| — Could I speak to Miss Smith, please? — ______. She's gone to the post office. |
A. I'm afraid not B. I think so C. Certainly you can D. I'm not sure |
答案
答案：A
搜题请搜索小程序“爱下问搜题”
| — Could I speak to Miss Smith, please? — ______. She's gone to the post office. |
A. I'm afraid not B. I think so C. Certainly you can D. I'm not sure |
答案：A
，斜面体上放一物块m，现对斜面体施加一水平作用力F，使物块与斜面体保持相对静止一起运动，不计一切摩擦，如图所示。则
