Sleep plays an important role in our life. A lack of sleep can influence our ability to work and study.

Normal people need 7 to 9 hours of sleep every night. But for teenagers, a healthy amount is about 8 to 10 hours. Sadly, only 1/3 of people manage that.

Tiredness usually reaches its highest twice a day, at 2 a. m. and 2 p. m. That explains why students easily fall asleep in afternoon classes. So sleeping at noon for a while helps us work better in the rest of the day.

People can make mistakes if they don't get enough sleep. Students cannot pay attention in class or do well in sports. Drivers who have fallen asleep while driving have caused 1% - 10% of the traffie accidents in our life. And we can imagine what will happen if a doctor feels sleepy at the operating table!

There are several ways that can help us sleep better, such as avoiding drinks that make us excited late in the day, going to sleep at the same time each night, and sleeping in a comfortable place that is dark, quiet and warm.

The passage mainly encourages us to (不得超过5个单词)

The earth is our home! Lingling and Tony had a lesson on the (环境) last week. After the lesson, they are (担心的) about the pollution. Pollution from (工厂) spreads over cities and villages. It does harm to our health.

There are so many cars on the roads and they use so much (石油) that causes pollution as well. In order to make the environment better, we should do something. Lingling thinks a green school can help to (改善) the pollution. At a green school, every class collets (废弃物) and it can be (回收利用). Students at a green school also learn ways to save energy at home. That means (较少的) waste.  They believe though pollution is heavy now, it is not (无望的). If everybody starts to do something, the world will be (挽救).

Turn on the tap and there is water. Getting water is so easy that you'd be1for thinking that there is2endless supply. But the world has a water shortage. 70% of the world is3with water. But most of this water is salt water4 only a small percentage (百分比) of5water. Many countries import (进口) water from other countries such as the US, Australia and Argentina.

This global shortage is predicted to get6as global temperatures rise.

Every person in the UK uses about 150 litres of water a day. Compare this7some countries where they only have 5- 10 litres! Poor countries would be8to hear that we use drinking water to wash our toilets. There are many simple ways that we can use to9our water use. Let's have a look at how we can help.

★Don't leave the tap running. We brush our teeth twice a day and by10the tap while we brush, we can save 5- 10 litres of water. 11every adult in the UK did this, then we'd12enough water for 500, 000 homes.

★Make use of rain.13rainwater in a water butt (桶) in your garden is a great way of reusing the water14plants healthy in summer.

★Reuse. Share bath water15your family to reduce costs and water use.

Elon Musk was born in 1971 in South Africa. At age 10, he developed an interest in computers. After teaching himself programming, Musk created his first piece of software (软件)before he turned 13. At 18, he moved to Canada and attended Queen's University at 19. He later went to the University of Pennsylvania to study economics and physics. Musk became a multimillionaire (千万富翁)after he sold his start-up company, Zip2, in 1999. He set up SpaceX in 2002. In 2012, SpaceX carried out the first commercial mission (商业任务). Since then, the company has carried out lots of missions for the International Space Station. On the last day of this May, the company sent astronauts there successfully for the first time.

Musk has set his sights on more than just space.     ▲     One of his greatest successes is Tesla Motors, which was founded in 2003. Tesla designs and produces electric cars. The cars are expensive now, but Musk's dream is to find a way to produce electric cars that are cheaper enough for more people to buy.

Musk is also trying to achieve a high speed way of travel called the Hyperloop, which. Can send passengers in a special train which moves at 700 miles an hour. The 380-mile trip from Los Angeles to San Francisco would take about 35 minutes.

Besides, he introduced a new kind of solar panel (太阳能电池板) for roofs (房顶) that would be cheaper than traditional roofing material. It would allow homeowners to collect energy from the sun." I believe in working super hard and not giving up. As long as I can see a path to success, I'll keep going," Musk said.