[email protected] wrote:It is possible that Native Americans originally have migrated
to the Western Hemisphere over a bridge of land that once
existed between Siberia and Alaska.

A. have migrated to the Western Hemisphere over a bridge
of land that once existed

B. were migrating to the Western Hemisphere over a bridge
of land that existed once

C. migrated over a bridge of land to the Western Hemisphere
that once existed

D. migrated to the Western Hemisphere over a bridge of land
that once existed

E. were migrating to the Western Hemisphere over a bridge

of land existing once


The answer is D for the reason:
This sentence uses the correct tense 'migrated' to
describe an action completed in the past.

My quetion is we say that we canuse present perfect tense to talk
about an action completed in the past but has some relevance in the
present. Will it not apply here ?

Actually I am a bit confused on when is present perfect correct as against
the usage of a past tense. Please explain...

[email protected] wrote:I have taken the GMAT. (or)
I took the GMAT.

Which one should I use ?

[email protected] wrote:In the post Ron says that present perfect can be used for a
completed action which has a direct bearing to an immediate
situation.

Now, this is what is not clear for me. I don't understand when
should I consider this as a completed action which has some relevance
to the current situation and when should I consider it as a completed
action in the past.

Could you let me know, please?

Thank you

[email protected] wrote:Let us suppose I gave my GMAT yesterday. Then, what do I say ?

I gave my GMAT yesterday. (or)
I have given my GMAT yesterday.

I feel the first one sounds good, but is the second one wrong? Why?

Could you let me know, please?