Geologists believe that the Bering land bridge, over which human being

harikrushna Kotadiya One way to think of this is that geologists are describing our current beliefs, so "are" is more appropriate than "were." From there, we can eliminate D because we're not just say "we think of them this way." We actually think that this happened, and it happened in the past.

However, all the "were" choices are wrong for other reasons, too. Both B and C seem to be applying "first" to "thought." This would mean that this is what we thought at first, when what we want to say is that we think this is where people entered first. Also, all three (B, C, E) seem to place "enter" and "thought" at the same time. In other words, people thought that humans were currently entering the Americas over the land bridge! This doesn't make sense.

The complex phrase "are thought to have entered" in A is needed to convey the complex relationship of events. It means we currently think something. What do we think? That humans first entered over the Bering Land Bridge before it disappeared 14,000 years ago. We could avoid some of this awkwardness if we had a subject--in other words, if we specified who was doing the thinking! Then we could say something like "Scientists think that humans first entered the Americas over the Bering Land Bridge, which they believe disappeared 14,000 years ago."
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Present perfect tense is about actions done in the past and stretch to the present but it is also about actions that ended in the past, period. I agree with Honghu's explanation and I will refer you to this link explaining present perfect: https://www.ccc.commnet.edu/grammar/tens ... erfect.htm
Look and scroll down the top right box.

Use present tense to express general truth.

Darwin discovered that theory of evolution is applicable to humans as well. ( even though the disovery happened in the past, it still holds true and hence the usage of present tense.).

E also has another problem . It is missing a have = "were thought to have first entered" would be correct.

Crick

Meaning,

the sentence is stating about Bering land bridge, which got disappeared due to environmental changes BUT people still consider that human being beings first entered Americas over that bridge.

"were " makes the sentence as if people used to think that the humans entered Americas over bridge but NOT NOW.
so, "are thought" will be used because THOUGH the bridge is no more BUT people still think that the bridge was first used by humans to enter Americas.

B - out because of wrong placement of "first"
C and D - awkward phrasing.

left with A and B

intuitively chose A, possible reasons: 1. "have entered" focuses on the result of the action
2. present tense looks better because of the wording "geologists believe". Interpreted this as generally people still think this way, although geologists believe something different which they have not proved yet.

but "disappeared about 14,000 years ago " can also be a genaral truth, why use the past tense?

yang
Let's consider some Dictionary definitions of past tense.

A tense expressing an action that has happened or a state that previously existed.--Oxford Dictionary

a verb tense expressing action or state in or as if in the past --- Merriam- Webster

The past tense is used to describe or indicate an action that began in the past. --- The free Dictionary

Therefore, a past tense may be about a truth that happened, but it will not be called a general truth. If it were a general truth, then such things should have happened in many other places. Eternal, perpetual, or universal happenings, which need the use of present tense, shouldn't be equated with general truths. "Disappeared 14000 years ago" is a specific truth but not a general truth. Hence, past tense.
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Dear Expert

kindly tell the correct concept. How OA is right and others wrong ?

We still continue to think that : human beings entered ................
Entrance of human being : Past action, hence entere dis correct..

Nothing wrong with the original sentence, answer will b (A).
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How to conclude that human beings are still considering that human being beings first entered Americas over that bridge.
Is there any hint in the non-underlined portion?

Geologists believe that the Bering land bridge, over which human beings are thought to have first entered the Americans, disappeared about 14,000 years ago when massive glaciers melted and caused the sea level to rise several hundred feet worldwide.

(A) are thought to have first entered - correct
(B) were thought first to enter
(C) were thought at first to enter
(D) are thought of as first entering
(E) were thought to first enter

imyuva, that's a good question. There's no clear indication that we still consider this to be true, nor is their any indication to the contrary. However, all of the choices that use the past tense are wrong for other reasons. Specifically, they all handle the "first entered" part incorrectly. B and C apply "first" to "thought," while E places "enter" in the present tense.
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"Bering land bridge, over which human beings are thought to have first entered the Americans,"


Hi guys . what is preposition "over" refer to ????
because "enter" comes with "in/into" and I do not know what is the role of preposition "over" before "which" . could anyone describe and rewrite the sentence informally .
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Damn.. this one really didn't make much sense to me "thought to have first entered the Americans"?! Why don't they say over which Americans are the first human beings thought to have entered....

subjective "were" is not required in this case as no wish is presented. Its seems to be a fact that human beings used the bridge to enter america so use are and not were. We can zero in on E that way

What is wrong with past tense. Understood simple present or present continuous for general truth but still confusing.

The past tense itself is not necessarily wrong in this context. After all, it could be that humans were thought to have entered over the land bridge but no longer are.

So, the past tense choices are all clearly incorrect for reasons other than the use of the past tense, as discussed in preceding posts.
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