Was vs Has been

Question

Introduce yourself please.

1. I have been a teacher for 10 years.

2. I was a teacher for 10 years.

Is the sentence 2 correct ? Can we use "for+period of time" with the past simple tense?

What is the difference between sentences 1 and 2 ?

Answer 1

Sentence 1 is present perfect. We use it when something happened in the past but some consequence remains, or the something is still happening:

I have booked some tickets - booking took place in the past, but the tickets are still valid
I have been looking for a new flat - I was looking and I am still looking or have only recently stopped.

Looking at your sentence:

1- I have been a teacher for 10 years.

This means that the speaker started as a teacher ten years ago and is still a teacher at the time of speaking, or has only recently stopped.

Sentence 2 uses simple past: we use this to talk about something that took place in the past, or that continued for some time but is now finished.

I fell off a ladder - a single event
I spent a month in Thailand - it lasted a month, but now it's over

Looking at your sentence:

2- I was a teacher for 10 years.

This means that the speaker became a teacher and stopped after ten years: this all happened in the past.

As you can see, it is possible to specify a time interval with simple past, as long as the time interval ended well before the time of speaking.

For more information, see the British Council explanation of talking about the past.