题目

 Senior citizens in that country enjoy certain_______, such as free medical care and free entry to public parks ? A. privileges     B. reputations       C. invitations      D. possessions 答案：A一个盛有盐水的容器中悬浮着一个鸡蛋，容器放在斜面上，如图所示．图上画出了几个力的方向，你认为鸡蛋所受浮力的方向应是A. F1 B. F2 C. F3 D. F4