tightens怎么读？

One set of provisions tightens emission standards.一套使排放标准更加严格的规定.Requires no special tools or fittings; hand tightens to relief valve outlet.不需要专用工具或管件; 用手将其紧固到安全阀上即可.The heart tightens at the grandeur we've already...

v.收紧( tighten的第三人称单数 )，（使）变紧，（使）绷紧，加紧...