什麼樣的狀況下，回答主詞要回答it

什麼樣的狀況下，回答主詞要回答it ？

除了事物、動物以外，可用It當主詞的用法如下：
1) 天氣
例如：It is rainy/sunny/windy. It is hot/cold.
2) 季節
例如：It is summer.
3) 時間
例如：It is nine-fifteen.
4) 距離
例如：It is ten miles from here.



2015-04-22 17:17:12 補充：
問句中的主體是this或that時，在答句中要改用it代之，例如：
What's that on the table?
It's an air-freshener.

It is a pronoun, neuter pronoun of the third person---its adj. belonging to it.
itself pronoun.-----emphatic form of IT.
eg:-Bird's feathers is collectively plumage pink color.Its plumage is pink.
its=possessive Adjective.
For pronoun case:-
Nominative:-it
Objective:-it
Possessive:-its as shown above eg.
Possessive Adjective:-its.
For impersonal mpronouns includ:-it, they, and them.
These can be used in place of nouns denoting a thing or things.Refer to the eg:-
if it is not personal, then
it is a fact.
It is an animal.
It is the weather.
It is time in the morning.
It is the distance involoved..
It is impersonal.
It is an object.
It is the bird's house.