鲫鱼是一种常见淡水鱼。下列关于“探究鲫鱼适应水中生活”的实验结论，正确的是（　　）

阅读下面文字，按要求作文。

       （一）在生活的旅程中，你也许拥有一些特别的收藏。或是一朵小红花、一张旧照片，或是一场经历、一段情谊，或是……它们承载着你成长的经历和温馨的记忆。请以“我的收藏”为题写一篇作文。

       （二）请以“如果我有         ”为题，写一篇作文。提示：先在横线上填写合适的词语，如：一双慧眼、一枝生花妙笔、比尔•盖茨的智慧、超强的记忆……

要求：①上面两题，任选一题，扣题作文。②文体自选（诗歌除外），不少于600字。③文中如需出现真实的人名、地名、校名等，请用化名代替。

如图所示，在窗框未安装好之前，木工师傅常常先在窗框上斜钉一根木条，其原因是（　　）

在离旗杆20米处的地方用测角仪测得旗杆顶的仰角为α，如果测角仪的高度为1.5米，那么旗杆的高度为____(用含α的代数式表示)

完形填空     Do you drink bottle water? How long does it1you to drink a bottle of water? Maybe just five minutes. But the plastic (塑料的) bottle will stay in nature(大自然) for 500 years! Plastic does not disappear (消失) 2 It is a big3 for humans.     There are many plastic things in our lives. They are cheap, light and easy to make.     Every year, the world uses 500 billion plastic bags. Every minute, we buy 1 million plastic bottles. The plastic we throw4 in one year can circle (环绕) Earth5!     For plastic things, the trash can (垃圾桶) is not 6 place they go in their lives. Every minute, a full truck of plastic things7into the sea. They make the seawa ter 8.They are dangerous for sea animals, too, 9when they eat.     So, is there10 useful we can do to help? Here are some tips.(小提示) First, carry your own cup to school. Second, take cloth (布的) bags to shopping, and buy fewer new toys, or you can exchange toys with your friends. Yes, just these small things, then you can help make the world a better place.