北師大版高中英語模塊7--Unit 21 Lesson1-1

[00:02.81]Unit 21 Human Biology Lesson 1 Chewing Gum [00:09.19]TO CHEW OR NOT TO CHEW... [00:12.21]Diet specialists regularly inform us [00:14.82]that it is important to chew our food properly. [00:17.74]They suggest that if we chew our food [00:19.77]until it is soft in our mouths [00:21.74]and then swallow it, [00:23.15]it will help our bodies digest it better. [00:25.96]So,does chewing gum have any effect [00:28.32]on this process? [00:30.52]One obvious benefit of chewing gum [00:32.71]is that it fights bad breath. [00:34.84]This is a problem for 50% [00:36.17]of the world's population. [00:38.29]According to some doctors, [00:39.84]if these people were to chew sugar-free gum, [00:42.44]it would help fight this embarrassing condition [00:45.18]Recently, some dentists have also claimed [00:47.56]that sugar-free gum, [00:49.33]if it has green plants materials added to itm, [00:52.24]helps to stop tooth decay. [00:54.15]The say that after eating, [00:55.64]acid attacks one's teeth. [00:57.80]Chewing gum makes your mouth wetter, [00:59.59]which then washes away this acid. [01:01.94]Therefore,they say,if people were [01:04.02]to chew sugar-free gum after a meal, [01:06.22]it would help prevent tooth trouble. [01:07.14]

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