I know that both
a) She has walked for two hours.
and
b) She has been walking for two hours.
mean the same thing: that she started walking two hours back and is still walking.
So according to the above example, both of the below two sentences should be correct.
- Since she started journey, she has felt sick.
- Since she started journey, she has been feeling sick.
But my grammar book says only the second sentence is correct. Why so? What is the difference in meaning between them?
Both are correct depending on the context.
Since "feel sick" is a continuous verb and there is an indicator of a duration of time,"Since she started journey," both present perfect and present perfect progressive are implying that it's an incessant event.
The only nuance difference is that present perfect could mean that she's not sick now, though it can also mean she may still be sick, whereas present perfect progressive can only mean that she is still ill.
For a start, both sentences are missing a definite article, the:
The time marker "since" puts the sentence in the Present Perfect Progressive tense and calls for the corresponding format.
See the image below from https://esllibrary.com/blog/present-perfect-vs-present-perfect-progressive/
I found this clear description from grammar-monster.com:
The present perfect progressive tense has two uses. It is used for:
A continuous activity that began in the past and continues into the present. For example:
- Those workmen have been fixing the roads.
A continuous activity that began in past but has now finished (usually very recently). For example:
- John has been baking cakes.
You have to rely on context to tell you whether the activity is still ongoing in the present or has finished. For example, the workmen might still be working, and John's finished cakes might be on the table.
See the below screenshot:
Both constructions are correct, but not for the obvious reasons. Besides the missing article in these two sentences, the difficulty is with the verb itself.
Corrected:
The present perfect (PP): An activity that has been completed in the past.
The present perfect continuous (PPC): An activity that has just been completed and has an impact on the immediate moment or continues into the future.
Option 2 leads us to empathize with the subject of this sentence:
Poor thing, she has been feeling sick since we left the house.
Whereas, the present perfect would do the opposite.
Fortunately, she has only felt sick once since we left the house. The journey has been quite easy for her.
So why is option 1 also correct?
Where everyone gets really confused is with respect to whether verb is active or stative.
The thing is that, when you are using a stative verb the PP is used instead of the PPC having the same meaning as the PPC. Stative verbs cannot be used with the continuous tense, regardless of whether it is present, future, past or perfect.
Correct:
- I am happy.
- I was happy.
- I will be happy.
- I have been happy.
It would be incorrect to say:
- I am being happy.
- I was being happy.
- I have been being happy.
I think the point is clear.
The problem is with the verb to feel. In theory, it is a stative verb, but in practice it is used as both stative and active.
Correct:
I feel happy.
Correct:
I am feeling happy.
Understanding this, wouldn't the PPC be correct then? Not necessarily!
If you follow example 1:
The PP would actually be correct and PPC incorrect.
If you follow example 2:
The PPC would be correct, and the PP would be quite weird.
In conclusion, there's no avoiding it. Both are perfectly correct.
I think because both sentence don't has a duration time like "for two hours/for two weeks". In this case, it can be used to emphasize an action that's been happening "lately" or "recently", so the present perfect continuous is more appropriate.
Both constructions are correct.
Your two walking examples should both say “has” and not “have”. Always “She has” or “She has been”; never “She have” or “She have been”.
