Teeth become loose and may fall out.

牙齿松动，可能会脱落。

youdao

Her dress has become loose, and she appears to have lost weight.

她的衣服变松了，看来是减肥了。

youdao

If the supporting bone is lost the teeth will become loose.

假若支持牙齿的骨头消失了，那么牙齿就会松动。

youdao

The raw materials are struck over and over until they become loose.

VOA: special.2009.07.06

"She's become unstable." "This is the disaster everyone warns about: a new species set loose in the world."

VOA: standard.2010.06.09

Have them replaced whenever they appear cracked, brittle, frayed, become loose or show signs of excessive wear.

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Asphalt shingles ( the most common roofing material in the U.S.) can become loose, cracked, be blown off by the wind or be damaged by hail.

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Weakened by the disruption of its finances and communications, with its base destroyed and its leaders in flight, it has become a loose and ever-shifting alliance of like-minded groups.

ECONOMIST: Weakened but still growing