bikes are red.          are blue.

如图所示，小明用50N的力F将重为80N的物体在5s时间内匀速提升1m，在此过程中，小明做的有用功为____ J，滑轮的机械效率　____ ，拉力做功的功率为____ W.

入射光线与镜面夹角为40°时，反射角为____；反射光线与入射光线夹角为60°时，入射角为____。

    It was the afternoon when we closed on our new house, and I was in the garage (车库). I 1 a part of blanket sticking out of the ceiling; that was 2 I pulled on it, and a way to the attic (阁楼) suddenly3 I climbed a ladder and headed up.

    I climbed into a space 4 the garage that was separated from the rest of the attic. As my eyes adjusted (适应) to the dark, I saw a metal container that I 5as a World War II ammo (弹药) box; my grandfather used to store 6used on his farm in this ammo boxes. I opened the cover and was 7 at what I saw: a lot of money 8 up in orange rope. God, I've found, like $800!

    But there was more than one box of9 I found another seven boxes10to the edge, plus two big black dustbin bags full of money.11 about $45,000. In my attic, I won't lie, my first 12 was that this was a 13 from God—the money to 14 this old house and to make life15for our two young sons. But I 16 that the right thing I should do was to17the money to the former owners. So I called them and asked them to come.

    They were18 of course, not only about the money but that I was returning it. They had recently 19 over the house and said it must have been their dad who had20 the money.

知己知彼____      运筹帷幄____       出其不意____

围魏救赵____      四面楚歌____       草木皆兵____