Today while watching TV, I came across this sentence,
Don't waste this summer watching TV.
The sentence seemed weird to me because in English grammar if you want to use progressive tense then you should use by, for, before, after etc. One more example:
Puppy fell asleep sucking his thumb.
Shouldn't that sentence have been like this:
Don't waste this summer by watching TV.
And the second one
Puppy fell asleep while sucking his thumb.
But I am only new to English grammar. So if I am wrong, please elaborate.