如图甲所示，一辆搬运砖头的独轮车，车箱和砖头所受总重力G=1200N，推车时人手向上的力F应为____ N．如图乙所示的动滑轮，支点为O，则动力臂L_F是阻力臂L_G的____ 倍．

阅读材料，回答问题。

    经过内蒙古全区各族人民的顽强拼搏，内蒙古的发展站在了一个新的历史起点上，全区已进入了全面建成小康社会的决胜阶段，在打造祖国北疆亮丽风景线的关键时期，更需要凝聚起加快发展的强大合力，共同谱写内蒙古发展的崭新篇章。

从方框中选择最佳选项完成对话。

A: What's the matter, Emma? Are you hurt?

B: I slipped on the stairs and fell down. ____

A: Oh, I hope not. ____

B: The left one.

A: ____

B: It hurts right here.

A: I think you'd better go to see the doctor and take an X-ray picture to see if there is something wrong with the bones.

B: ____

A: Of course. Let's go at once.

B: ____

A: Let's go by taxi.

B: All right.