It is polite for students to put their hands in class if they have questions．
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real pleasure pioneer invent daily |
Paul： Hey， Jenny， the subject for my school project is "Small inventions that changed the world"． Can you help me think of an invention？
Jenny： With（1） ! Let me think …hmm …I know! The zipper!
Paul： The zipper？ Is it（2） such a great invention？
Jenny： Think about how often it's used in our（3） lives． You can see zippers on dresses， trousers， shoes， bags …almost everywhere! I saw a website last week． The（4） of different inventions were listed there．For example，it mentioned that the zipper was（5） by Whitcomb Judson in 1893． But at that time， it wasn't used widely．
Paul： So when did it become popular？
Jenny： Around 1917．
Mr．Smith （亲吻）his wife and kids before he goes to work every day．
Liu Chuanjian is considered a （英雄）because he safely landed the damaged plane．
Who is （敲）at the door？
Maybe it's the postman．
I can't hear you （清楚地）． Please speak a little bit louder．