became后加形容词做表语；用作连系动词，其后可接名词、形容词、过去分词等作表语：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。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