@1jane1,
1jane1 wrote:
if someone could explain to me what is the difference in these two sentences and which one sounds more grammatically correct! Thanks a lot!
Both are equally correct.
Both are describing a situation in the past where a person did something (watched) at the same time as something happened (pages were blown away)
1. He watched the wind blow his pages away.
This sentence uses a first verb (watched) followed a noun (wind) followed by the infinitive or base form of a verb (blow). We can only do this with certain first verbs: feel, hear, help, let, make, see, and watch.
I felt the phone vibrate
She heard the bell ring
You helped me climb the stairs
They let me sleep
The teacher made me work
I will see the sun rise
You watched me run
2. He watched as the wind blew his pages away.
This sentence uses a first verb (watched) followed by a conjunction (as) (we can use while) which we can use for saying that something happens at the same time as something else, followed by the simple past tense of a verb (blew). This way of describing things happening at the same time can use any first verb.
I waited while the paint dried
We danced as the music played
He sang as he worked
The drunk man swayed as he walked
Nero fiddled while Rome burned
Both ways are acceptable.