He was down in the mouth because he missed his train.

他因为没赶上火车而闷闷不乐。

youdao

Because he looks down in the mouth.

因为他总是往嘴里看。

youdao

Since her dog died, Susan has been down in the mouth.

苏珊的狗死了后，她一直愁眉苦脸的，闷闷不乐的。

youdao

If this should happen, the speaker might feel down in the mouth.

VOA: special.2010.06.20

Occasionally he grimaces, as if he were biting down on the golden flames in his mouth.

NEWYORKER: Baptizing the Gun

The biopsies can be done through an endoscopy, in which a fiber-optic tube is placed in the mouth and down into the small bowel or through some even less invasive procedures.

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Visitors Hull KR received a boost before kick-off, both with the signing of Australian international Willie Mason and the news that rivals Hull FC had gone down to defeat earlier in the day to set up a mouth-watering Humberside derby play-off clash next weekend.

BBC: Crusaders 30-24 Hull Kingston Rovers