序号 | 支持面 | 木块对支持面的压力/N | 滑动摩擦力/N |
① | 棉布 | 2 | |
② | 木板 | 4 | |
③ | 玻璃板 | 6 | |
④ | (a) | (b) |
In the universe, as we all know, there is the Sun, the Moon, the Earth and a good many stars. Through our geography lessons, we know the Earth goes around the Sun, and the Moon goes around the Earth. We have day and night because the Earth keeps turning all the time. When our part of the Earth turns to the Sun, it is day. When our part of the Earth turns away from the Sun, it is night.
Just because the Moon is closer to the Earth than the Sun, it looks much bigger than the Sun. Big things will look smaller when they are further, and small things also look bigger when they are nearer.
The Sun is big enough to give out very strong light. The Moon can't give out any light at all, but it looks quite bright, too. Why? In fact, the light from the Moon comes from the Sun. The Moon looks much bigger and brighter than the stars. But actually the stars are much bigger and brighter than the Moon. They look smaller than the Moon also because they are farther away from the Earth.
There are many other planets in the universe. But of all the planets, only on the Earth there are living things and people can only live on the Earth, too. But at 9: 00 a. m. on October 15th, 2003, Chinese pilot Yang Liwei was sent up to space. He stayed there for over 21 hours. It was the first time for Chinese to get into space.
走一步,再走一步(节选)
①时间在慢慢地过去。影子在慢慢拉长,太阳已经没在西边低矮的树梢下,夜幕开始隆临。周围一片寂静,我趴在岩石上,神情huǎng hū,害怕和疲劳已经让我麻木, 我一动也不动,甚至无法思考怎样下去,安全地回家。
②暮色中,第一颗星星出现在天空中,悬崖下面的地面开始变得模糊。不过,树林中闪烁着一道手电筒发出的光,然后我听到杰里和爸爸的喊声,爸爸!但是他能做什么?他是个粗壮的中年人,他爬不上来,即使他爬上来了,又能怎样?
③爸爸远远地站在悬崖脚下,这样才能看见我,他用手电筒照着我,然后喊道:“现在,下来,”他用非常正常的、安慰的口吻说道:“要吃晚饭了。”
④“我不行!我会掉下去的!我会掉死的!”我大哭着说。
⑤“你能爬上去,你就能下来,我会给你照亮。”
⑥“不,我不行!太远了,太困难了!我做不到!”我怒吼着。
⑦“听我说,”爸爸继续说,“不要想有多选,有多困难,你需要想的是迈一小步,这个你能做到。看着手电光指的地方,看到那块石头没有?”光柱游走,指着岩脊下面的一块突出的石头。“看到了吗?”他大声问道。
⑧我慢慢地挪动了一下,“看到了。”我回答。
⑨“好的,现在转过身去,然后用左脚踩住那块石头。这就是你要做的。它就在你下面一点儿。你能做到,不要担心接下来的事情,也不要往下看,先走好第一步。相信我。”
⑩这看起来我能做到。我往后移动了一下,用左脚小心翼翼地感觉着岩石,然后找到了。“很好。”爸爸喊道,“现在,往右边下面一点儿,那儿有另外一个落脚点,就几英寸远。移动你的右脚,慢慢地往下,这就是你要做的,只想着接下来的这步,不要想别的。”我照做了。“好了,现在松开左手,然后抓住后面的小树干,就在边上,看我手电照的地方,这就是你要做的。”再一次,我做到了。
⑪就这样,一次一步,一次换一个地方落脚,按照他说的往下爬,爸爸强调每次我只需要做一个简单的动作,从来不让我有机会停下来思考下面的路还很长,他一直在告诉我,接下来要做的事情我能做。
爸爸远远地站着,。
爸爸用手电指着突出的石头,。
爸爸要求“我”,。
①生命十分宝贵,只属于自己 ②珍爱他人的生命如同珍爱自己的生命 ③只有自己和亲人的生命才是最重要的 ④我们要尊重、关注、关怀和善待身边的每个人
2015•乐山)如图为“塔斯马尼亚岛等高线及其铜矿带分布图”.该岛山地面积广,耕地面积狭小,常年受西风(图中箭头所示)影响,气候温和,森林覆盖率高,自然环境优美.在一幅等高线地形图上,等高距不一定相同,相对于城市甲,城市乙成为港口理想建设地的主要优势条件是( )