It would not be a complete sentence but, there is nothing inherently grammatically incorrect in the phrase "during the all period". What you have is a reference to a period of time called "the all". Just because nobody knows what "The All" is doesn't make this grammatically incorrect.
No, it is not grammatically correct to say "during the all period." The correct phrasing would be "during the entire period" or "throughout the entire period."
No, it is not grammatically correct to say "what all do you expect." A more correct way to phrase this question would be: "What do you expect?" or "What are your expectations?"
No, the phrase "of which we are all" is not grammatically correct. It would be better to say "of which we all are" or simply "which we all are."
The sentence "Is he is woeful" is not grammatically correct. It should be "Is he woeful?"
Yes, the sentence is grammatically correct. It conveys a positive expression of anticipation to meet a group of people in the future.
Yes, the phrase "please see attached letter" is grammatically correct. However, it might be more formal to say "please find attached the letter" or "I have attached the letter for your reference."
All it needs is a question mark. Have you had lunch? That is grammatically correct.
yes
No not at all
yup...
Short answer : Yes and not impolite at all, as suggested below. This is to be handled by you grammatically correct? requires inverted commas to be correct. It should be written as: "Is this sentence "This is to be handled by you." grammatically correct?" The sentence is correct but not very polite; it would be simpler to say "You are to handle this"
It certainly can be correct. As with all grammar it depends on how it is used
It can be, but not all the time.
Only in the south.
Grammatically, yes.
No, it is not grammatically correct to say "what all do you expect." A more correct way to phrase this question would be: "What do you expect?" or "What are your expectations?"
Yes, it's fine.
It wouldn't be grammatically correct.