【单选题】There was a big pile of bricks on the top of a tall building and a man had to bring them down to the ground. He had a long rope which went over a pulley(滑轮) at the roof of the building. The other end ...
A.
He was afraid that someone would steal his box.
B.
Because he wanted to climb up along the rope.
C.
He fastened the end of the rope in order to keep the box unmoved.
D.
Because he wanted to prevent the box from coming down.
【简答题】In a nice house there lived an old man. Behind the house there was a big garden. He planted many plants there. He took care of his 41 all the time, watering and fertilizing (施肥) them. One day a young ...
【单选题】There was a big pile of bricks on the top of a tall building and a man had to bring them down to the ground. He had a long rope which went over a pulley (滑轮) at the roof of the building. The other end...
A.
He was afraid that someone would steal his box.
B.
Because he wanted to climb up along the rope.
C.
He fastened the end of the rope in order to keep the box unmoved.
D.
Because he wanted to prevent the box from coming down.
【单选题】Once a man and his wife worked for a businessman. There was a big box in the business-man-s living room. The businessman pointed at the box and said,'There's only one thing you(11) do.Don't open the b...
【单选题】(2016·四川高考)如图 2 所示,正六边形abcdef区域内有垂直于纸面的匀强磁场。一带正电的粒子从f点沿fd方向射入磁场区域,当速度大小为v b 时,从b点离开磁场,在磁场中运动的时间为t b ,当速度大小为v c 时,从c点离开磁场,在磁场中运动的时间为t c ,不计粒子重力。则 ( )