人教版九年级英语上册《When was it invented?》SectionB PPT教学课件(第1课时)，共23页。
Warming-up
A: When was the… invented?
B: It was invented in…
A: Who was it invented by?
B: It was invented by ...
A: What was it used for?
B: It was used for ...
Summary
1. key words & expressions:
sour, customer, by mistake, in the end
2. Sentence:
① Potato chips were invented by mistake.
② The customer was happy in the end.
3.Functions: To give students listening and speaking practice.
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