1、一般现在时
1.1、表习惯性动作;人或事物的特性或状态;客观真理等
Everyone is in high spirits. Light travels more quickly than sound.
1.2、用于时间和条件状语从句，代替一般将来时
If it is fine tomorrow， we will go on a picnic. When you come next time， bring me some magazines.
1.3、与具有“出发，到达”含义的动词连用，表示按计划将要发生的动作
The delegation arrives in Beijing this afternoon. There is a new film tonight.
2、一般过去时(表示过去某时间的动作或状态)
The children went out just now. She died ten years ago. I lost my wallet at the theatre.