2. bacteria pest discovery nutrition root 1. Some __________ can cause disease. People usually take some medicine to help them to recover. 2. If someone makes a _________, he or she is the first person to find or become aware of something that no one knew about before. 3. Stores of grain are frequently attacked by _______, especially rats. 4. Some vegetables are grown for their ________ which are large and can be eaten. 5. Nowadays people eat more food made of grain because of its_________. bacteria discovery pests roots nutrition

3. 1 Why are chemical fertilizers so popular in farming today? 2 What problems can be caused by using chemical fertilizers? 3 What is organic farming? 4 What is the main reason for using organic farming methods? Read the passage and answer the following questions.

4. 1 Why are chemical fertilizers so popular in farming today? They are a great way to stop crop disease and increase production.

5. 2 What problems can be caused by using chemical fertilizers? First, they can damage the land by killing helpful bacteria and pets. Second, because of staying in the ground and underground water for a long time, they damage people's health by building up in their bodies and leading to cancer or other illnesses. Third, fruit, vegetables and other food may grow too fast to be full of nutrition.

6. 3 What is organic farming? 4 What is the main reason for using organic farming methods? Organic farming means growing crops without using any chemicals. The main reason for using organic farming methods is to grow good food and to avoid damaging the environment or people’s health.

7. Find and write down the methods and advantages in the passage. Methods of organic farming Advantages of methods Farmers use natural waste from animals. This makes the soil richer in minerals and so more fertile.

8. Methods of organic farming Advantages of methods 1 Farmers use natural waste from animals. 1 This makes the soil richer in minerals and so more fertile. 2 Farmers often change the kind of crop in each field every few years. 2 Changing the crops renews the minerals in the soil and helps it become rich and healthy.

9. Methods of organic farming Advantages of methods 3 Farmers plant crops with different lengths of roots. 3 This uses different levels of soil. 4 Farmers sometimes plant grass between crops and leave it in the ground. 4 This prevents wind or water from carrying away soil and acts as a natural fertilizer.

10. build up: 逐渐增强；积聚； 建立； 开发 1. 这些锻炼有助于增强你的腿部力量。 2. 温室气体逐渐在大气层聚集， 从而引起全球气 温上升。 focus on : pay special attention to 集中（注意 力、精力）于 1. 请集中精力思考下列问题。 2.be/stay/ keep/remain focused on 集中于， 集 中到 虽然开玩笑，但大部分时间他们的精力都集中在这 个话题上。

11. 3.lead to: have sth as its result 导致结果；造 成 毫无疑问，心里压力会导致生理疾病。 4.keep…free of/from: protect…from 使 … 免 受（影响；伤害） 我们应该使用新能源以保持环境不受污染。