A good way to pass an exam is to work hard every day in a year. You may fail in an exam if you are lazy for most of the year and then work hard only a few days before the exam. If you want to be good at English, you have to read stories in English, and to speak English as much as possible. A few days before the exam you should go to bed early. Do not go to bed late at night. Before you start answering in the exam, read carefully over the question papers, and try to understand the meaning of each question. When you have finished your exam, read over your answers. Correct the mistakes and be sure that you don't miss anything out.

如图是某同学设计的实验室制取氧气的实验装置图，请回答下列问题：

（1）分液漏斗的优点：____ 

（2）二氧化锰在该化学反应中的作用是____ 

（3）组装好A装置后，该同学先向分液漏斗中加入水，然后将导管另一端浸入水中，并打开分液漏斗的活塞，观察导管口是否有连续的气泡冒出，该操作的目的是____ ．

（4）A装置中发生反应的化学方程式为　____ ，氧气能用B图收集的原因是____ ，应将收集满氧气的集气瓶____ 放在桌面上．

阅读下面的材料，根据要求作文。

    就像海明威的《老人与海》中的桑地亚哥一样，人生总不是一帆风顺的，总是充满崎岖坎坷和挑战的。在面临困难挫折的时候，或许你坚持了，你奋斗了，但最后一无所获。或许你选择了放弃……

请以“人生需要                        ”为题写一篇议论文。

要求：①请补全题目，再写作。②800字以上。③不得套作，不得抄袭。