1、所有或任何时候都发生的动作或情况,即重复发生的动作
--- How often does she visit her parents?
--- Twice a month.
2、永恒的真理
Summer follows spring.
3、①在条件或时间状语从句中
I’ll let you know as soon as he gets there.
②讨论计划和时间表或日程表时
We leave at 11:15 and arrive at 17:50 tomorrow.
4、固定词组如 I see(明白)、I hear(听说)、I think(认为、想)、I feel(感觉)以引出已经了解的情况
I see there’s some trouble in London.