1. 用作连系动词,其后可接名词、形容词、过去分词等作表语。如:He became a teacher at (the age of) 17. 他17岁就当了老师。The weather became warmer. 天气变得暖和起来。Soon the roombecame crowded. 不一会儿房里就挤满了人。注意:其后接过去分词时,可表示被动或结果;但表示被动时,其后一般不接 by短语。比如不说 Soon the room became crowded by students.
2. become 是终止性动词,因此要表示“成为…有多长时间”有多长时间,英语不能将become与表示一段时间的词或短语连用。如:

他成为老师有十年了。正:He became a teacher ten years ago. 正:It’s ten years since he became a teacher. 正:He has been a teacher for ten years. 误:He has become a teacher for ten years. 3. become 之后一般不接不定式表示“逐渐…” (此时可用 come, begin+不定式)。如:+不定式正:He began [came] to like English. 他开始喜欢英语起来。误:He became to like English. 正:He became ill yesterday. 他昨天病了。误:He became to be ill yesterday. 4. 用于习语 become of, 表示“发生”、“遭遇”等 (常与 what连用)。如:What has become of the girl? 这个女孩后来怎样了?
Idon’t know what will become of me if I fail this time. 要是我这次不成功,我不知我会怎么样。