top是上衣的意思，而shirt则是衬衫的意思，区别可以从以下例子看出：

Please put on a shirt for our party, you can't just wear top for this party, you need to show your respect for the host and yourself. 请为我们的派对穿上衬衫，你不能只穿上衣参加这个派对，你需要表达对主人和你自己的尊重。