题目

听一段材料，回答下列三个小题。【1】How did the old man come to Shiyan?A.By plane. B.By bus. C.By train.【2】Where does the old man’s daughter work?A.In a big park. B.In a hospital. C.In the train station.【3】Why can’t the old man find his daughter’s home?A.Because Shiyan has changed a lot.B.Because he has never been to Shiyan.C.Because his daughter moved to a new house.如图所示，木块m放在木板AB上，开始θ=0，现在木板A端用一个竖直向上的力F使木板绕B端逆时针缓慢转动（B端不滑动）。在m相对AB保持静止的过程中 [     ]A．木块m对木板AB的作用力逐渐减小 B．木块m受到的静摩擦力随θ呈线性增大 C．竖直向上的拉力F保持不变 D．拉力F的力矩先逐渐增大再逐渐减小