tighten

动词 tighten:

1. make tight or tighter
   同义词：fasten
2. become tight or tighter
3. restrict
   同义词：stiffen, tighten up, constrain
4. narrow or limit
   同义词：reduce

1. He tightened his grip on her arm.
   他紧抓她的手臂。
2. Controls in the city have gradually tightened.
   对这个城市的控制逐渐加强。
3. This screw needs tightening.
   这螺丝钉需要再拧紧些。