4.一个直角三角形的斜边长为8，内切圆半径为1，则这个三角形的周长等于 (    )

如图所示，两个壁厚可忽略的圆柱形金属筒A和B套在一起，底部到顶部的高度为18cm，两者横截面积相等，光滑接触且不漏气．将A用绳系于天花板上，用一块绝热板托住B，使它们内部密封的气体压强与外界大气压相同，均为1.0×10⁵Pa，然后缓慢松开绝热板，让B下沉，当B下沉了2cm时，停止下沉并处于静止状态．求：

下列各句中，没有语病的一项是（  ）

假如你是收银员，请根据菜单给Lucy和Mary结一下账吧！
Waitress: Good morning. Can I help you?
Lucy: Yes, I want a hot dog. Do you want a hot dog, too, Mary?
Mary: No, I don't like hot dogs. I want two hamburgers.
Waitress: And to drink?
Lucy: A cola for me, please.
Mary: And I want some milk, please.
Waitress: OK. Anything else?
Lucy and Mary: No, thanks.

easy  eye  good  interest  late  learn  something  they  why  with

    Most children like watching TV. It's very ____  . By watching TV they can see and learn a lot and know many things about ____ country and the world. Of course, they can also ____ over the radio. But they can learn better and more ____ on TV. ____  ? Because they can hear and watch at the same time. But they can't see ____ over the radio. TV helps to open children's ____ . It helps to open their minds, too. They learn newer and ____  ways of doing things. Many children watch TV only on Saturday or Sunday evening. They are always busy  ____ their lessons. But a few children watch TV every night. They go to bed very ____. They can' t have a good rest. How about you, my young friend?