has become。因为has后面要接动词的过去分词形式，动词become的过去分词是become，became是动词become的过去式。become作及物动词时意为“成为；变得；变成”，第三人称单数变化是becomes；现在分词形式是becoming。

has become的例句

The environment has become a very hot issue.

环境已成为很热门的话题。

The Internet has become part of everyday life.

互联网已成为日常生活的一部分。

The new office block has become an expensive white elephant.

这座新办公大楼成了昂贵的摆设。

May Day has become a venerable institution

五朔节已经变成一个神圣庄严的传统节日。

The programme has become a firm favourite with young people.

这个节目已着实赢得了年轻人的喜爱。

become相关短语

become rich疾速致富；迅速致富；火速致富；神速致富

become extinct灭绝；变坏；绝种

has become成长为；已经成为；已变成；已经变成

become conscious醒悟；恢复知觉

become weak手发软；变得萎靡不振；倦怠；变弱

become invalid作废；成为无效；变得无效；这药已失效了