make sth. more strict
The government has issued new politics to toughen the rules about using electric scooters.
toughen =toughen up
The new law toughens up penalties and restrictions for DUI offenders.(DUI=driving under influence酒驾)
toughen常加policy/rule/penalty/punishment 等名词
作业：
1.The government has gradually toughen the regulation of car-hailing services.
2.Grand companies have gradually toughen the rules of construction.
