It's not a good idea to change this file unless you know what you are doing.to change this 是不定式作主语 not a good idea 是表语,后面的unless you know what you are doing.又是什么成分呢?是单独接的一句话吗?
最近看到Believe it or not, his discovery has created a stir inthe scientific circle.还有 Be rich or poor, I will marry him anyway.这两个句子包含的语法点是一样的吗?是怎么样的用法呢,是在虚拟语气看到的。