Digestion begins in the mouth with the action of saliva.

消化是在口腔中唾液的作用下开始的。

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Poor digestion can be caused by defective mastication of the food in the mouth.

消化不良可能是因为嘴里的食物没有完全嚼碎而引起的。

《柯林斯英汉双解大词典》

Digestion actually starts in the mouth, so the more work you do up there, the less you’ll have to do in your stomach. This can help lead to fewer digestive problems.

如果吃得慢,就将食物嚼得更细,就更利于消化.消化其实是从嘴里开始的,所以在嘴里的准备做得越足,胃的负担就越小.这样还能避免不少消化毛病.

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Apparently, the drug can be absorbed both through the tissues in the mouth, and of course, digestion.

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