251. 太阳既发光又发热。The sun sends out both light and heat.

　　252. 美国过去发射过许多宇宙飞船。America used to send up many spaceships.

　　253. 是该分出好坏的时候了。It’s time to separate the good from the bad.

　　254. 该释放他们的时间了。It’s time to set them free.

　　255. 直到我看见他们启程才回来。I didn’t come back until I saw them set off.

　　256. 我们打算早上出发。We are going to set out in the morning.

　　257. 他们肩并肩地走进了教室。They went into the classroom side by side.

　　258. 我会随身带些钱以便买些吃的。I will bring some money with me so as to buy something to eat.

　　259. 就我所知，他不但是老师还是作家。So far as I know, he is not only a teacher but also a writer.

　　268. 我想要为你送行。I would like to see you off.

　　269. 你必须尽快卖光所有的票。You have to sell out all the tickets as soon as possible.

　　270. 你为什么不立刻派人请医生呢?Why don’t you send for a doctor right now?

　　271. 我的车有点毛病，所以我不能加速。There is something wrong with my car, so I can’t speed up.

　　272. US 代表美国。US stands for the United States.

　　273. 别说话了，该上课了。Stop talking. It’s time for class.

　　274. 咱们停下来休息一下。Let’s stop to have a rest.

　　275. 北京有许多名胜古迹，比如长城、颐和园等等。There are a lot of places of interest in Beijing, such as the Great Wall, the Summer Palace and so on.

　　276. 请你把它拿走好吗?Would you please take it away?

　　277. 别紧张，我会帮你学英语的。Take it easy! I will help you with English.

　　278. 屋里很冷，你最好别脱下外套。It’s verycold in the room, you had better not take off your coat.279. 我们可以从容地为考试做准备。We can take our time to get ready for the test.

　　280. 他取出了一些照片。He took out some photos.

　　281. 昨天发生了一起交通事故。A traffic accident took place yesterday.

　　282. 我取代了他。I took the place of him.

　　283. 每天玩电脑游戏占用许多时间。Playing computer games takes up a lot of time every day.

　　284. 我经常一出去就关灯。I often turn off the light as soon as I go out.

　　285. 刚才，我阻止了他开灯。I stopped him from turning on lights just now.

　　286. 他把电视开得很大声。He turned up TV very loudly.

　　287. 我看见她在教室里走来走去。I saw her walk up and down in the classroom.

　　288. 我以前怕黑。I used to be afraid of the dark.

　　289. 我习惯晚饭后去散步。I am used to going for a walk after supper.

　　290. 我很抱歉让你等了这么长时间。I am sorry to keep you waiting for me so long time.

　　291. 这道数学题太难，我做不出来。This math problem is too difficult for me to work out.

　　292. 我一点都不担心我的英语。I don’t worry about my English at all.

　　293. 你最好记下地址。You had better write down the address.

　　294. 如果可以的话，我会经常给你写信。I will write to you as often as possible.

　　295. 总之，忘记不高兴的事，继续努力学习。In a word, forget the unhappy thing and keep on working hard at your lessons.

　　296. 我相信如果你努力，一定会成功的。I'm sure you can be successful if you try your best.

　　297. 你读的书越多，你获得的知识就越多。The more books you read, the more knowledge you will get.

　　298. 很高兴收到你的来信。Nice to hear from you.

　　299. 只要你用心，没有什么是不可能的。Nothing is impossible if you put your heart into it.

　　300. 我期待你的好消息。I’m looking forward to your good news.