北师大版高中英语模块7--Unit 21 Lesson1-1

（单词翻译）

[00:02.81]Unit 21 Human Biology Lesson 1 Chewing Gum¹
[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 embarrassing² 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 decay³.
[00:54.15]The say that after eating,
[00:55.64]acid⁴ 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]