It's a lot of work. That is a complete sentence. Some teachers prefer that you use another word rather than "a lot." Like, "It's quite a bit of work." or "It's much work."
It's a lot of work. (correct) Don't aggravate you. (incorrect, you should be yourself) You like the movies a lot. (correct) She is smarter than he is. (correct, it is implied 'She is smarter than he is smart.')
Does your brother work in a hospital? is the correct sentence.
Jerry handed the instructions to the boys and me.
The sentence "I have many friends." is a correct sentence. An alternate would be, "I have a lot of friends".
You have done much work on this new software project
It depends how you use it. If you use it after something it can be correct. But being in a sentence by itself isn't correct.
yes
yeah , i think is correct say a lot of thanks for quick response...
the men have done a lot of work or the men will do a lot of work both of these work fine
no you can try they had a lot of fun and so did you.
your work has definietly correct
"A lot" is singular, and it is the subject, so the verb is singular too: "has."