在英语语法中，能够做主语的成分包括以下几种：
名词（或名词词组）
单数可数名词：例如：My pen is green.
复数可数名词：例如：Students are playing soccer.
专有名词：例如：Jane is an American girl.
名词短语：例如：The route went through the city.
代词
主格人称代词：例如：I am a student.
宾格代词：例如：You are late.
反身代词：例如：She prepared the meal herself.
指示代词：例如：This is a gift for you.
物主代词：例如：His book is on the table.
疑问代词：例如：Who is speaking, please？
数词
基数词：例如：Two will be enough.
序数词：例如：First, let's clean the room.
动名词（或动名词短语）
例如：Swimming is my favorite sport.
例如：Her hobby is collecting stamps.
动词不定式（或动词不定式短语）
例如：To learn English well is important.
例如：I came to see you.
从句
主语从句：例如：What he said at the meeting is very important.
表语从句：例如：The problem is that we don't have enough time.
同位语从句：例如：The fact that he is a liar is obvious.
这些成分可以在不同的句型中充当主语，例如陈述句、疑问句、倒装句、祈使句和感叹句等。在特定情况下，如疑问句或倒装句，主语可能会位于谓语动词之后或省略。
建议
在实际应用中，选择合适的主语成分可以提高句子的清晰度和表达的准确性。理解并掌握这些语法规则，可以帮助你更好地进行英语写作和口语表达。
