it

      （指提到过的或正在谈论的动物或事物）它used to refer to an animal or a thing that has already been mentioned or that is being talked about now

      （指婴儿，尤指性别不详者）used to refer to a baby, especially one whose sex is not known

      （指已知或正在发生的事实或情况）used to refer to a fact or situation that is already known or happening

      （用以明确身份）used to identify a person

      （用作形式主语或形式宾语，而真正的主语或宾语在句末）used in the position of the subject or object of a verb when the real subject or object is at the end of the sentence

      （谈论时间、日期、距离、天气等时用作主语）used in the position of the subject of a verb when you are talking about time, the date, distance, the weather, etc.

      （谈论情况时用）used when you are talking about a situation

      （强调句子的某部分）used to emphasize any part of a sentence

      正好是所需的；恰好exactly what is needed