完成时态的常用时间状语包括"By + 时间点/时间段"表示在某时间点或时间段前完成,"Since + 时间点"表示从某时间点开始至现在,"For + 时间段"表示持续的时间段,"Already"表示动作或状态已完成,"Just"表示动作或状态刚刚完成。掌握这些时间状语有助于准确表达过去的动作或状态已完成的时间。
- By + 时间点/时间段
"By"表示在某个时间点或时间段之前完成的意思,常用于完成时态中。例如:
- I will have finished my work by 5:00 pm.
- They will have been married for 10 years by next month.
- Since + 时间点
"Since"表示从某个时间点开始一直到现在的时间,常用于完成时态中。例如:
- I have been studying English since last year.
- He has been living in China since 2010.
- For + 时间段
"For"表示持续的时间段,常用于完成时态中。例如:
- I have been working here for 5 years.
- They have been playing tennis for 2 hours.
- Already
"Already"表示动作或状态已经完成,经常和完成时态连用。例如:
- I have already finished my homework.
- They have already eaten dinner.
- Just
"Just"表示动作或状态刚刚完成,常用于完成时态中。例如:
- I have just arrived at the airport.
- He has just left the room.