【例1】用方框中所给单词的适当形式完成句子
produce，product，production
1. The of cars needs a lot of workers.
2. This is one of the most popular in our store.
3. Farmers sell fresh at the local market.

1. production 2. products 3. produce

【例2】选词填空
Some scientists worked hard for many years to (invent/discover) useful
machines.
【答案】invent

invent