The european ban on iranian oil imports tightens the screw .

欧盟对伊朗石油的禁运进一步收紧了绳索。

If it now tightens , it risks compounding the recession .

如果它现在收紧政策，它将面临加剧经济衰退的风险。

The relatively liberal emirate tightens its rules against kissing in public

相对自由的酋长国收紧规则，禁止在公共场所接吻

Laughter tightens your stomach muscles .

大笑能够收紧腹肌。

Joints stiffen as their molecular mesh of collagen tightens , the same process that helped to strengthen them in early life .

关节的胶原蛋白分子网格收紧造成了关节僵硬；同一过程在生命初期有助于强化关节。