The new law was introduced in 1991.
这项新法律是于1991年开始实施的'。
The system was introduced on a trial basis for one month.
这个制度已引进试行一个月。
There are bound to be changes when the new system is introduced.
引进新系统后一定会发生变化。
It was announced that new speed restrictions would be introduced.
据宣布，将有新的限速规定出台。
The government is ready to introduce protection for the car industry.
政府准备对汽车工业实行贸易保护。