英语完形填空Barack Obama was elected to be the nee presindent of A

A.became
become的中文含义是：成为；变成.
　　例句：He quickly became tired and sat down to rest.
　　　他很快就感到疲劳并坐下来休息.
　　become,get和turn都有“变成”的含义,但是它们的用法不尽相同.
　　（1）become常用在书面语里,get常用于口语中.如：
　　Jack and I met on holiday and became good friends.
　　杰克和我在假期中相遇并成为好朋友.
　　Your dinner's getting cold.
　　你的饭菜都凉了.

显然用become会比较正式
　　
（2）turn表示“变成”时是系动词,后跟表语,强调的是质的变化.become表示“变成”时也为系动词,后接表语,强调的是状态变化.如：
　　The trees have turned green.
　　那些树已经变绿了.
　　It is becoming warmer and warmer.
　　天气变得越来越暖和.
而keep不合题意.

A,变成