1. While people in other countries in the world were trying to catch wild animals and birds and were still collecting seeds and nuts, farmers in China were developing the science of agriculture. 当别的国家的人们还在努力捕猎禽兽、采集果实时，中国的农民就已经在从事农业研究了。
了解引导时间从句的三个引导词 when, while, as 的区别: while 的含义是during the time that 表示时间段或过程，强调主句与从句的行为或状态同时发生或存在，从句的谓语动词必须是延续性的。如：While I was reading, the telephone rang. 我正看书时电话响了。when 的含义是at or during that time, 既可以用于指时间一点(从句谓语需用终止性动词),也可用于指时间段(从句谓语需用延续性动词)。如：When the firefighters arrived, we had already put out the big fire. 当救火队员到来时，我们已经把大火扑灭了(前后两个动作不同时发生)。When I woke up, Mum was preparing breakfast. 当我醒来时，妈妈正在准备早餐。as 侧重的是主句和从句中的行为同时发生，通常译为随着...或一边...一边...。如: As you grow, you know more and more. 随着年龄的增长，你的知识越来越丰富。
2. He advised farmers to choose the best seed-heads, the ones that had the best colour. 他建议农民挑选最好的谷穗，即那些颜色最好的谷穗。
the ones在本句中是同位语，后接定语从句。如：He offered me some books, the ones that are both interesting and instructive. 他提供给我一些书籍，既有趣又有教育意义。My mother advises me to make good friends, the ones that can help each other. 我母亲建议我交好朋友，也就是能互相帮助的朋友。
1. Whats the weather going to be like at the weekend? 周末的天气怎样？问天气也可用How is the weather going to be?
2. Then he returned home and spent his time on research into agriculture. 然后他回到家乡，把时间用在农业研究上。research into对进行研究：The doctor carried out a research into healthy food. 这位大夫对健康食品进行了研究。
3. He collected information, studied it, did experiments and learnt from the experiences of farmers. 他收集、研究资料，进行实验，并学习农民的经验。experience 有两个意思：①经历(可数)：He told us about his experiences in Africa. 他给我们讲述了他在非洲的经历。②经验(通常不可数)：Have you got much experience in/of teaching? 你教学经验丰富吗？
4. Then he said that they should be hung up to dry. 他说这些谷穗应挂起来晾干。掌握hang的用法：①悬挂(hung; hung): She hung her wet clothes out on the line. 她把湿衣服晾在绳子上。The trees were thickly hung with fruit. 树上果实累累。②吊死(hanged; hanged): He was hanged for murder. 他因谋杀而被绞死。
5. In the following spring, the seeds should be knocked out of the seed-heads and sown. 第二年春天，种子应该从谷穗上敲打下来，然后播种。形容词following 紧接着、下一个: It rained on the day we arrived, but the following day was sunny. 我们到达的那天正下雨，但次日天气晴朗。
6. He studied how to improve soil conditions. 他还研究了怎样改造土壤状况。condition 作单数的时候，表示人或物所处的具体状态，这时候它的意义相当于state.如：The doctor said that the patient was in good condition. 医生说病人状况不错。用作复数时，指一般情况，偏重于环境。如：They were interested in living conditions in Canada. 他们对加拿大的居住环境感兴趣。
7. Here are five pieces of advice collected from Jia Sixies book Qi Min Yao Shu: 这是从贾思勰的《齐民要术》一书收集到的五条建议：这是倒装句。又：Here are some examples. 这里有一些例子。Heres your watch. 这是你的手表。但主语是代词不倒装：Here they are. 再提醒：不能说advices或an advice，应说 some advice 或 a piece of advice。
8. But if you plant rice in a field one year and wheat in the field the next year, you will harvest good crops. 但如果你头一年在这块地里种水稻，第二年则在这块地里种小麦，就会获得好收成。掌握harvest的用法：①名词：gather in the harvest of corn 收获玉米；have another good harvest 又有一个好收成 ②动词：The farmers are out harvesting the corn. 农民们在外收割庄稼。