become的过去式
vi.
become的变形
become
[bi'kʌm]
vi.
成为，变为，开始变得，变成，转为：
She became ill.
她生病了。
Halen became famous.
海伦成名了。
The weather in spring became warmer.
春天天气变得更暖和了。
She became tired and went to bed.
她疲劳得去睡觉了。
逐渐成为，逐渐变成(或发展成为)：
The tadpole has become a frog.