用法：
1.用作連系動詞，其后可接名詞、形容詞、過去分詞等作表語：
He became a teacher at (the age of)17.他17歲就當了老師。
The weather became warmer.天氣變得暖和起來。
注意：其后接過去分詞時，可表示被動或結果；但表示被動時，其后一般不接by短語。比如不說：
Soon the room became crowded bystudents.
2.become是終止性動詞，因此要表示“成為…有多長時間”，英語不能將become與表示一段時間的詞或短語連用：
他成為老師有十年了。
正：He became a teacher ten years ago.
正：It’s ten years since he became a teacher.
誤：He has become a teacher for ten years.
3.become之后一般不接不定式表示“逐漸…”(此時可用come/begin＋不定式)：
正：He began [came] to like English.他開始喜歡英語起來。
誤：He became to like English.
正：He became ill yesterday.他昨天病了。
誤：He became to be ill yesterday.
4.用于習語becomeof,表示“發生”、“遭遇”等(常與what連用)：
What has become of the girl?這個女孩后來怎樣了?
I don’t know what will become of me if I fail this time.要是我這次不成功，我不知我會怎么樣。