Sentence Correction

Hi rx_11,

Your definition of present perfect tense is correct. However, one more key aspect needs to be included. Present perfect tense is also used for events that happened sometime in the past but whose effects still continue into the present.

As an example, "The teacher has posted solutions on the board"

In this sentence, the action of actually posting the solutions is completed. However the effect of that action is still on. And that is why present perfect tense is used.

Contrast this with "The teacher posted solutions on the board"
In this sentence, we know the teacher completed the action of posting solutions. But we are not certain whether the effect is still on. That is whether the solutions are still posted or not.

On similar lines,
"profits have increased" in the sentence in question implies that profits increased in the past but the effect is still on. In essence, no other action happened to the profits - they are still in that increased state.

I hope this helps.

For e-GMAT users, this along with other examples has been used to explain the concept of present perfect tenses in the concept titled "Verb Tenses - I".

Regards,

Payal

Hi rx_11,

From the meaning of the sentence, the action of "were first discovered in 1932" is indeed a DISCRETE event in the past. Notice the phrase "in 1932". This phrase indicates that this action took place at a certain time in the past time frame.

Present perfect tense is considered correct for the action of "found". Essentially the sentence implies the following (only partial meaning shown)
The Clovis Points have been found in all of North America since they were first discovered at a New Mexico site in 1932.

There are multiple actions in this sentence:
1: Clovis points have been found
2: they are named
3: They were first discovered in 1932

So if we sequence these events: We come up with the following chronological sequence:
1: They were first discovered in 1932
2: Clovis points have been found
3: they are named

Thus, the discovery of Clovis points took place in 1932 in Mexico. Once discovered, these points were then found all over North America.

Thus, as you can see there is an action - found - that took place after the action of discovery in a certain location. This also implies that the effect of "discovery" is no longer on since another action on the same object - Clovis points - has already taken place.

I hope this helps.

Regards,

Payal

Choice C does not communicate the intended contrast in the original choice.

Original Sentence:

• Even though Clovis points are found all over North America
  they are named for the site where they were first discovered.

The contrast is clearly evident in the original sentence.

Choice C:
Two facts about Clovis points:

• They are named for the site where they were first discovered
  They have been found all over North America

This choice is worded to state these two statements as independent facts about Clovis points. Hence the intended contrast is not expressed in this sentence.

I hope this helps.

Regards,

Payal