Could you tell me the difference in meaning of these questions please?

When and in which situations can we use them?

  1. He seemed to have felt very tired.

  2. He seems to have felt very tired.

When we say:

  1. He seems as if he knew the answer.

It means like we think he does not know the answer. Can we keep on implying this meaning by using:

  • seem + infinitive form

For example can we say:

  1. He seems to knew the answer.
  1. He seemed to have felt very tired.

  2. He seems to have felt very tired.

The first one is fine. Sentence 2 mixes the present tense with the past tense, and you may not want to do that. Let's examine Sentence 1:

He seemed to have felt very tired.

(I suppose it might sound a bit more natural to say, "He seemed to be tired," or, "He looked very tired," but I don't find your version "ungrammatical." It simple recounts an observation from the past.)

If we are making an observation in the present, though, we might say:

He seems to feel very tired.

(although a native might be more likely to say "He seems to be tired," than, "He seems to feel tired")

Here's another sentence with a similar construct. Suppose you watch a figure skating routine that impresses you, but the skater's marks turn out surprisingly low. You might say:

He seemed to have skated very well. I'm surprised he didn't get better marks.

During the routine, however, you might have said it in the present tense:

He seems to be skating very well. I expect he will earn excellent marks.

Notice how seemed to have is used to reference the past, while seems to be references the present.

Applying that to the student who seems to know the answer:

  1. He seemed as if he knew the answer. (past tense)
  2. He seems as though he knows the answer. (present tense)

When we remove the "as if" or "as though," however, the tense of the verb "seem" tells us if we are referencing the past or the present. The word "know", being part of an infinitive, stays in the present tense in both cases:

  1. He seemed to know the answer. (past)
  2. He seems to know the answer. (present)

which is why others were so quick to point out that #4 is incorrect.


1- He seems to have felt very tired.

2- He seemed to have felt very tired.

Both the sentences express a similar idea, with the only difference that their verbs indicate different times. The former sentence shows the present tense, which has the same meaning as "he seems that he has felt very tired". Whereas, the latter one shows the past tense, which has the same meaning as "he seemed that he had felt very tired".

3- "He seems as if he knew the answer". The verb "knew" in the as if clause is in the subjuntive mood. It means that he gives the impression that he knows the answer, but he prabably does not know or we don't know whether he knows or not.

4- "He seems to knew the answer" doesn't make sense, hence grammatically incorrect. We should use to-infinitive here, so the correct sentence is "he seems to know the answer".


First off, in response to your first two sentences, the difference is in the time frame of the subject. The first sentence, "he seemed to have felt very tired," basically means that at a point in the past, you had the impression that "he" felt tired at the specific time that you were observing him. A better sentence to say would just be, "He must have been very tired." This states the same condition and meaning as the first sentence, but with better flow and less length. The second sentence, "He seems to have felt very tired," means that the person who you are observing was tired or felt tired previous to you seeing him or observing his behavior in the present. Again, the better sentence to say would be exactly the same: "He must have been very tired." In both cases this is the much more informal statement of your observations and comes out much smoother in verbal and written form.

Second, in response to your next question, it's not that we don't think that he knew the answer, rather we think he did based on how he answered the question, or how he behaved following his statement of the answer. In certain situations, if you used a sarcastic tone, it could be said that you didn't think he knew the answer. But without sarcasm, we can't assume that the observer thought that the individual didn't know the answer.

And in response to your last sentence, this is not grammatically correct because your time frame conditions do not match. You would have to say either "He seems to know the answer" or "he seemed to have known the answer." I hope this answers your questions.

  • I disagree that "He must have been very tired" is a better way to express this. The word "must" is used when there's zero doubt about the cause of the condition. A mother might say: Cory seemed to have been very tired, so we told him to take a nap. A week later, though, we took him to the doctor, and found out he had diabetes. The mom uses "seemed" to convey that she initially misdiagnosed the illness. You might say something similar about a new co-worker: He seemed to have been very tired, but later we learned he was always grumpy. In such cases, we might say, "He acted very tired..._
    – J.R.
    Nov 18 '14 at 8:29

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