...意思,那么这句话 If someone such as a postman or
milkman has been, they have called at your house.和If someone such as a postman or milkman is here, they
will call at your house. 这两句话一个是都是现在完成时,一个是主将从现,请问他们表达的意思有什么不同...
In summer, flowers and plants growing in luxuriance in my small courtyard will leave little open space as a playground for the little cats. 请问该句中的 flowers and plants growing in luxuriance in my small courtyard 是主语吗,这个结构如何理解呢,谢谢。