Learn English – Direct and indirect speech

backshiftingdirect-speechmodal-verbsreported-speech

Have I changed the direct speech into indirect correctly?

Direct:

He said,"If I had a pen,I could write the answer."

Indirect:

He said if he had had a pen,he could have written the answer."

The part that says "he could have written the answer" implies an impossible case however "could write" is improbable not impossible, so we have changed an improbable case into in an impossible and it doesn't make sense to me!
However, I'm not that sure,could you help please.
Thanks.

Best Answer

He said that if he had had a pen, he could have written the letter. (= possibility)

This means that if he had had a pen at that point in time, he would've had the possibility to have written the letter, but not neccessarily have written the letter. It implies that he would've had the choice to write or not write the letter (if a pen had been available to him).

If you say

He said that if he had had a pen, he would have been able to write the letter.(= ability)

This implies that he would have had the ability to write the letter, and says nothing about his choice to do or not do so.