题型:判断题 — Do you ask why I am learning English?— Yes, I mean, what are you going to do with it? Are you going to be a teacher of English or something like ?[ ]A. itB. himC. thatD. such 查看答案
题型:判断题 如图所示,AC是上端带定滑轮的固定竖直杆,质量不计的轻杆BC一端通过铰链固定在C点,另一端B悬挂一重为G的重物,且B端系有一根轻绳并绕过定滑轮A,用力F拉绳,开始时∠BCA>90°,现使∠BCA缓慢变小,直到杆BC接近竖直杆AC。此过程中,杆BC所受的力[ ]A.大小不变 B.逐渐增大 C.先减小后增大 D.先增大后减小 查看答案