1 . Water is important for our body and health. It is important because almost all parts of the human body have water. And about 60%-70% of our body is made from water. ①If there is no enough water, our body _________ work properly. ②We can get it through several ways, such as having fruit, vegetables, tea and milk. How much water do we need every day? It is different every day. It depends on our daily activities and the temperature of the day. Generally speaking, an adult needs about eight cups of water every day. ③But when we do some exercise or when the temperature is high, __________.

2 . From goldfish to sharks, fish of all sizes have lived on Earth for hundreds of millions of years. But do they ever get thirsty?

The answer is yes! Some fish do, at least. But there is a big difference between fish that live in saltwater and ones that live in freshwater.

Bony fish have some salt concentration（含盐量）in their bodies. For bony fish in saltwater, their concentration is lower than the water they live in. Through osmosis（渗透作用）these fish will lose lots of water through their bodies. In order to make up for this loss, they drink lots of water, so it’s easy to say that they can be thirsty. Although drinking saltwater is never a good idea for humans, fish can drink it because they can get rid of the salt through their gills（鳃）.

But sharks are an exception. Sharks can make their salt concentration match the water around them. They do this by building up urea（尿素）in their blood, so they probably don’t get very thirsty. But blood with a high salt concentration can also be bad. The high concentration means sharks won’t do very well in freshwater—water can enter the sharks’ bodies by osmosis and even cause them to explode!

Freshwater fish, on the other hand, are unlikely to become thirsty. Because they live in a less salty environment, they have a different problem: water goes inwards and dilutes（冲淡）their blood. Freshwater fish therefore need to get rid of this extra water. So now we know that saltwater fish can become thirsty and drink water, while freshwater fish will avoid drinking but pee（小便）a lot.

What are some things in your life that give you too much stress? Find out what you can do about it.

School Work and Grades

As a student, school work and grades are at the top of your stress list. Even if your school grades are not so bad, you may still fear that you may not do as well as you expect. Heavily learning burden is another cause for worry.

Why not take it easy by leaving extra time to study and take frequent breaks to avoid being so tired? Manage your time carefully and do not put things off.

Friendships and Relationships

Have you ever been concerned with not having enough friends,or not being in the same class as your best friends? These, along with other issues such as peer pressure and interpersonal disagreements and arguments, are other common stress.

It is important to know how to choose your circle of friends wisely. Do not “hide” in your own “nest”. Make friends when you join school activities. Make plans to meet with your friends from other classes during break time. Know that everyone is unique and different—do not compare yourself with others.

Poor Diet and Lack of Sleep

Do you know that eating too much fast food and junk food can lead to mood changes, lack of energy and other negative effects? These convenience food which have less nutrition (营养) may cause other health issues. Some students suffer from sleep problems too. When that happens, they behave poorly in class.

Learn to make wise food choices that you can enjoy. Well plan and arrange your daily routine. Completing all school tasks, going to bed at a set time every night. Avoid playing computer games or smartphone before you sleep. Do see a doctor if your sleeping problems continue.

7 . It’s been over a year since COVID-19 first appeared and the virus continues to be a problem in many parts of the world,scientists have realized the development of vaccines (疫苗) is a solution to the pandemic. A global effort to vaccinate as many people as possible would be needed, since vaccines typically take years to develop.

On Dec 2, 2020, the first COVID vaccine, the Pfizer vaccine, was approved (批准) by UK health department. However, these vaccines must be stored at very low temperatures, which is not possible everywhere. In response, Chinese companies like Sinopharm and Sinovac have developed vaccines that can be kept at normal temperatures.

Now, vaccines are being rolled out all over the world, with millions of people being vaccinated every day. In China, 285 million vaccine doses (剂量) had been given so far. Meanwhile, the US has given out 247 million doses. The UK now stands at 50 million doses.

Although there have been rumors about vaccines being unsafe, most of people seem to realize the importance of vaccination for building mass immunity (群体免疫) in order to stop the virus from spreading. The world has come to understand that the vaccines will protect us. Therefore, sharing vaccines has become a key factor of staying safe and healthy worldwide.

Unfortunately, not everyone can get the vaccine yet. Children below the age of 16 can’t be vaccinated because they have not yet been tested on them. Those who have a history of vaccine allergies (过敏) shouldn’t get it, either.

8 . Pollution is a serious problem nowadays. It affects our lives and makes many animals in danger. We should do something to help reduce pollution: But what should we do? The following ideas may help.

1. Tell your family, your friends and other people you know to make as less rubbish as they can.

2. Recycle as much “waste” as you can. Or don’t buy things which will become waste. You can use plates made of china and forks made of steel thousands of times. Plastic plates and knives last once and then become waste.

3. If you want to go somewhere, try to walk or use a bicycle. Cars are big polluters for air pollution.

4. See if you can buy food which has been grown locally. Some farmers deliver vegetables and other foods. Buying local foods means almost no transport is needed.

5. Some shops and supermarkets will deliver things to your home. You can even shop online. This means your family doesn’t need to drive to pick up your food. One supermarket truck can bring things to many families...saving lots of car journeys. Think about it.