题海网，海量题库；找题库、找试卷、找答案就上题海网。

有一个重7N的铁球，当它浸没在水中时受到的浮力多大？（ρ _铁 =7.9×10³kg/m³ ）

阅读理解

It's normal to long for the taste of potato chips or a cheese –covered pizza. Even though they're full of calories, eating them occasionally won't do much harm. However, according to the new numbers, young people are becoming more gluttonous. The BBC's Good Food Nation Survey showed that on average, 16 to 20-year-olds ate fast food at least twice a day in the UK. So what's behind this fast food binge (狂热).

WebMD, an online publisher of news and information of human health and well-being, surveyed nearly 600 teenagers and adults in the United States. They found that the most common reason was our busy lifestyle. More than 92.3 percent of respondents said they were too busy to cook. Many find it challenging to balance work and life, and the convenience of fast food meets their needs. Fast food is readily available in corner stores and vending machines (自动售货机).

Remember those instant noodle cups from the supermarket? They're ready in minutes, and you can store them at home for a long time.

But many people think this trend does no good. Sarah Toule, head of health information at World Cancer Research Fund, told the BBC: "It's frightening that people, especially younger generations, are eating so much fast food loaded with fat, sugar and salt, but offers little nutritional value."

She added, "Especially high in calories, fast food leads to unhealthy weight gain – which in turn increase the risk of 11 cancers later in life.

So what is the right thing to do? Toule suggested that young people should prepare meals in advance and learn to include the different food groups in their diets.

The sign "NO FISHING" near the pond means "___________".

同温同压下，若2体积单质气体A₂和1体积单质气体B₂化合生成2体积气体C，则C的化学式为（   ）

   

请将下列错误实验操作可能导致的后果填在对应的横线上．

A．腐蚀标签    B．引起火灾    C．滤液浑浊    D．瓶底炸裂

甲、乙两同学用质量相同的铁板和铝板，制作容积相同的两只模型船，它们都漂浮在水面上，受到的浮力大小关系是F_甲F_乙 ， 它们能运载水的最大质量关系是M_甲M_乙。(均选填“＞”“<”或“＝”)

下图反映1950年——2010年间，发达国家比发展中国家（   ）  

等比数列中, ， 则的前4项和为（   ）

She（visit）the Tianchi Lake last year.

阅读下文，回答问题。

侯宝林妙语连珠观瀑布

    1985年5月，受国人爱戴的相声艺术大师侯宝林，在大瀑布涨水的日子里来到黄果树。人人都想亲睹大师的风采。

    我有幸陪着侯老游览景区。一路上我除了介绍景观景点外，还有机会领略侯老妙语连珠的语言艺术。

    说话间，我们到了大瀑布前象鼻岭看台，侯老突然抬手说：“同志，你备有微型雨刮器吗？”当时我真是“丈二和尚摸不着头脑”，正不知如何作答，跟随的人群猛然大笑起来，这时我才看清他摘下了眼镜，正用镜布擦镜片上的积水呢……嗬！原来瀑布的水珠迎面扑来，打湿了眼镜，这才使侯老爆出“微型雨刮器”的问题。我才回过神来，这不正是一个相声“包袱”吗？

    进了水帘洞，站在第一个洞窗，仰看从天而降的瀑布，一片雪白的水帘遮住了洞口，我大声说：“这是水帘洞最大的洞窗，现在水大，瀑水集成一块帘布，完全把洞口蒙住了，但随着水量的变化，水帘就会随水的大小关上或打开，对面的景色一览无余。”他风趣地说：“真妙啊！这个水帘还是自动化的嘛！”侯老的“包袱”一出，又赚得一片笑声。

    往前走四五米，到了“听瀑洞”，我当即请侯老听瀑布的轰隆隆水响，那轰鸣就像军乐队在打铜鼓一样，侯老说：“对的，我听见了，我的耳朵很好噢！我听到了雄伟的进行曲啦！”大家的笑声再次和瀑布声共鸣。

下图为某大陆沿某一线的年降水量变化示意图。读图，完成下列各题。

默写填空。

选择合适的单词，补全句子。(只填序号)

A. B.  C.  D.  E.  

阅读下面材料，在空白处填入适当的内容(1个单词)或括号内单词的正确形式。

Chinese tea is good for cleaning our digestive system. From time time, we would like to have a cup of Chinese tea after meal. Sometimes, we use Chinese tea for cooking, especially tea eggs.

Tea eggs, a popular Chinese food, (sell) along the busy sidewalk or at a market food stand. It is not only a quick and delicious way to fill up your stomach, a unique way to learn Chinese culture of food.

Chinese tea eggs are easy to make. Simply prepare some (boil) eggs. Gently tap the egg shells with the back of a teaspoon and crack the shells. Next, (careful) place the cracked eggs in the pot with marinade (卤汁) and boil for about 15 minutes. Then let the eggs soak (浸泡) in the (mix) for about 4 hours, makes the eggs have enough flavor. The dark color of the marinade gives the egg a marbled effect. Before (serve), gently reheat the eggs with the marinade.

Although a tea egg comes from China and  (have) much to do with Chinese cuisine (烹饪), other similar recipes have been developed throughout Asia.

am, you, in, I, meet, going, Beijing, to (.)（连词成句）

在1949年的国统区，经常可以看到人们带着大捆大捆的金圆券去购买日用品，对人们的这一行为发生的原因的理解，正确的是（）

茶树喜温暖、好雨雾、怕积涝、耐酸怯碱。我国茶树种植面积广大，下图为我国四大茶区分布图。读图，完成下面小题。

关于《昆虫记》的描述，不正确的一项是（     ）

已知点列 满足： ， 是自然数，且 ， ， .