题目

It’s raining heavily. Who’s _____ my umbrella? A. brought             B. got C. taken             D. carried 答案：C 11．水平桌面上一质量为1kg的长方体，用4N的水平拉力向右拉，长方体静止不动，此时它所受的摩擦力为4N；拉力增大至8N时长方体做匀速直线运动；若拉力增大至10N时长方体所受的摩擦力为8N．