Hi guys, I need some help!

I came across a multiple-choice question. I can't figure out why the offered answer is correct. Can anybody throw some light on it.thanks!

Land animals are believed to__ sea animals.
A. have been developed from
B. have developed into
C. have developed from
D. develop from
The given answer is C. I am wondering why the answer D is not correct

Thanks again!

The sense is not correct, although grammatically it would be. We are talking about a geo-historical process, thus the past tense is needed.

D would suggest that this happens all the time, that every land animal used to be a sea animal earlier in its life.

that would be a fun world to live in

Land animals are believed to have developed from sea animals.

Land animals are -> passive voice, which requires

believed -> past participle of "to believe"

to have developed -> past perfect

The rest is immaterial, but it's unlikely that "into" is the correct answer. :)

Past Perfect is used to describe an action in the past that preceedes another action in the past (the belief);
I am not a grammaticist. I can't even spell grammaticist. But I'm reasonably sure that's correct.

Land animals are believed to__ sea animals.
A. have been developed from
B. have developed into
C. have developed from
D. develop from

Land animals are believed to have been deveoped from sea animals. This implies that some other person or thing did the developing.

Land animals are believed to have developed into sea animals Land animals came first; then sea animals developed. This is not factually correct.

Land animals are believed to have developed from sea animals As noted, this is grammatically correct. Scientists believe tht lad animals developed form sea animals, but there is always a chance they are wrong.

Land animals are believed to develop from sea animals It happened in the past and is still happening now.

Land animals developed from sea animals Not one of your choices, but is also correct if yo want ot imply that this is known for certain..

I instantly thought that D was incorrect for the reasons given -more concisely than I could - by Mathilda and Shiglia. Particulary why D wasn't correct.

I got it. Thanks!

It is the present perfect tense, not the past perfect.

The present perfect tense describes something from the past which is still current or relevant or has an effect on the present.

The belief originated in the past and is still a current belief.

The auxillary verb has or have and the past participle

The belief originated in the past and is still a current belief.

But that has nothing to do with the present perfect tense here. "Land animals are believed" is in the present tense because we are speaking about current beliefs.

Compare:

Whales are believed to have developed from land animals.

The Gypsies were believed to have migrated from Egypt.

Maggots were believed to be generated spontaneously out of rotten cheese.

'are believed' indicates the passive voice, to me, and the 'have developed' the present perfect.

I am not sure what you are objecting to. I did say the present perfect tense.

Your two last examples are past tense

Are you saying the OPs example is not a perfect tense? The present simple tense would be 'We believe that land animals develop from sea animals'.

Edited by: billybart

#10 -- What I'm saying is that your statements

The present perfect tense describes something from the past which is still current or relevant or has an effect on the present.

The belief originated in the past and is still a current belief.

imply that the fact that the belief originated in the past and is still a current belief has something to do with the occurence of the present perfect "have developed" in OP's example. It doesn't. The fact that the belief is a current belief is reflected in the tense (present) of the passive verb "are believed." If the belief were no longer a current belief, you would use "were believed." If it were relevant that the belief originated int eh past and was still current, you would have a sentence like this:

Whales have long been believed to have developed from land animals.

The present simple tense would be 'We believe that land animals develop from sea animals'

You're mixing up tense and voice. "are believed" is present simple, so is "we believe". The first is passive, the second is passive. For past passives and present perfect passives, see #11.

We will have to agree to disagree on this, but I think that you should read up on perfect tenses.
Not voice.

Present Perfect With verbs of state that begin in the past and lead up to and include the present
To express habitual or continued action
With events occuring at an indefinited or unspecified time in the past -- with ever, never, before

He has lived here for many years.
He has worn glasses all his life.
Have you ever been to Tokyo before?

Yes, but have you read it? 'have developed'

For you, billybart.

Uh, yes. Which should make it clear that the verb that refers to "belief" in OP's examples is present simple passive, not present perfect.

Personally I can't imagine a sentence I would be less likely to write or say than "Whales have long been believed to have developed from land animals." Even though it is probably grammatical, it is about as ugly as it gets, language wise.