has 是什么时态

　　His quality of life has improved dramatically since the operation.

　　手术后他的'生活质量大大改善了。

　　A new system has been devised to control traffic in the city.

　　控制城市交通的新系统已经设计出来。

　　The company has a long tradition of fine design.

　　这家公司的优秀设计历史悠久。

　　The country has a poor record on human rights.

　　这个国家人权记录不佳。

　　The information has been placed in the public domain.

　　这资料不受版权保护。