it作形式主语句型 — 英语选择题
题目
下列句子中，it 作形式主语的一项是（ ）
A. It often snows in winter in Harbin.
B. It is exciting to make a snowman with friends in winter.
C. — What's the weather like today? — It is windy.
D. Look at the bird! It is flying south for the winter.