Unit 9 When was it invented? Section A 3a-4 Learning goals:Use the sentences “What do you think is the most helpful / annoying invention? I think the most helpful / annoying invention is .” to talk about some inventions.Step 1 Preview List some inventions with students. Then let students ask and answer with the following sentences in groups. 温故知新Step 2 PresentationShow a picture of an alarm clock. And ask students.What is this in the picture? What is it used for? Do you
