[General] I could not

[suniljain]

I could not understand the topic.

I didn't understand the topic.

I understand the 1st sentences relates to present situation whereas 2nd one relates to past situation. Am I correct?

 

[MikeNewYork]

For me, they both relate to the past.

 

[emsr2d2]

They both refer to the past. To refer to the present, you would use:

I cannot/can't understand the topic.
I do not/don't understand the topic.

 

[suniljain]

For me, they both relate to the past.

I could not understand the topic.

I didn't understand the topic.

Does it mean that these sentences convey the same meaning?

 

[Tarheel]

They really say the same thing.