I am puzzled!1.Is this Jim?No, he isn't.2.Is this your sister?No, it isn't.The two dialogues appear in our American-edited English book,so I wonder why “he” is used in the first dialogue, but “it“ in the second?

熱心網友

只有當提問人無法確定被提問對象的身份時候才這樣用我有免費英文資料下載，可以去看看，單擊我的名字（雪花啤酒）就可以看到。謝謝！

熱心網友

In American English, "it" and "he/she/I" usage can be confusing sometimes for people who are not familiar with that。 Two dialogues refer to the similar situation and they are correct。 It is not a dramatic difference between those two。 For example, when you call someone on the phone, you don't say "Who are you?" instead you say "Who is this?" When you answer the phone, you say "this is Mary", but you don't say "I am Mary"。 Therefore, "it/that/this" can use it to describe "he/she/I"。

熱心網友

其實沒有什么區別