原文：
Organic farmers also use many other methods to keep the soil fertile. They often change the kind of crop in each field every few years, for example, growing corn or wheat and then the next year peas or soybeans. Crops such as peas or soybeans put important minerals back into the soil, making it ready for crops such as wheat or corn that need rich and fertile soil. ___4____. Some organic farmers prefer planting grass between crops to prevent wind or water from carrying away the soil, and then leaving it in the ground to become a natural fertilizer for the next year's crop. ___5_____.
5.因果关系： so/ therefore, thus, consequently, as a result (of), so/ such ...that ..., so that ...等
Strategies
策略
① 篇章结构类
结构 相关词、结论词句、句式特点
关键词同（义同词义、词反、义反词义、词同、畴同词畴、词、 代词、同词复现）
