1,学校门卫交给了我一封信

1. The school gatekeeper gave me a letter . 动作发生在过去,用过去时态.
2. He is lying on the grass . 正在发生,用现在进行.
3. He has just washed his clothes . 动作发生在过去,结果影响到现在,用现在完成时.
4.Have they travelled by train ? 同上