题目

—They didn’t go to the park yesterday.           —___________.          A. So we did     B. So did we    C. Neither we did     D. Neither did we 答案：D丝绸摩擦过的玻璃棒靠近一轻质小球，发现两者互相排斥，由此可鉴定A. 小球一定带正电 B. 小球一定带负电 C. 小球可能带负电，也可能带正电 D. 小球一定不带电