early
1.early in the morning等表达方式有时被用作名词。例如：Early in the morning is a good time for a walk.
2.下面两句意思相同：
They arrived here early in the morning.
They arrived here in the early morning.
下面两句也意思相同：
Early next morning we started together.
Next morning early we started together.
3.as early as five o'clock和as early as 1632里不该在five o'clock前面加上at或在1632前面加上in。
4.I was told that he had left the city two days earlier里的earlier作before解。