it作句子的真正主语语法
1.it 指前面已经提到过的人或事物，有时指心目中的或成为问题的.人或事物，作真正主语。
例如：
What’s this? -It is a sheep? 这是什么??这是一只绵羊。
Who is it? -It’s me (I). 谁??是我。
It’s the wind shaking the window. 是风刮得窗户响。
2.it指时间、季节。一般用在无人称动词的主语。
例如：
What time is it? -It’s nine. 几点了??九点了。
It’s time for the meeting. Let’s go. 开会的时间到了，我们走吧。
What day is today? -It’s Saturday. 今天星期几??今天星期六。
What’s the date today? -It is October 1st.
今天是几号? ?今天是十月一日。
What season is it? -It is summer. 现在是什么季节??是夏季。
3.it 指气候。一般作无人称动词的主语。
例如：
Is it cold in this room? -No, it isn’t. 屋里冷吗??不冷。
What’s the weather like today? -It is fine.
今天天气怎么样??是晴天。
It often rains in summer and it often snows in winter in this city.
这个城市夏天经常下雨，冬天经常下雪。
4.it指距离、情况等。一般用作无人称动词的主语。
例如：
It is five kilometers from my home to the school.
从我家到学校有五公里。
It is very near from this factory to that one.
从这个工厂到那个工厂非常近。
It is a long way to the sea. 离海很远。
Is it well with you? 你身体好吗?