题目

如图所示，倾角为q的斜面上固定有一竖直挡板，重为G的光滑小球静止时，挡板对球的弹力大小为FN1，斜面对球的弹力大小为FN2，则（       ）（A）FN1＝Gtanq          （B）FN1＝Gsinq（C）FN2＝Gcosq          （D）FN2＝Gsinq  答案：A解析:略 27.[2000上海] The ________ boy was last seen ________ near the East Lake. A. missing; playing B. missing; play C. missed; played   D. missed; to play