Use "much" to describe a relative amount of a noun that can't be easily counted or quantified. If you can't put a number before the noun, use "much."
Also, if you replace the object with a pronoun, it should be singular (it). Consider "collective nouns" that are singular but describe an unquantifiable volume.
"Much" is often combined with a modifier like "too," "not," or "very."
There is not much snow on the ski slopes this year. It's a small amount.
There's much work ahead before the end of the project. It's a big one!
There's too much sand on the beach to count it all. It's everywhere!
"Many" describes a quantifiable, countable noun. If you can put a number before the noun you should probably use "many." Here if you replace the object with a pronoun, it will be plural (them, they).
Many ski-lift operators will be looking for jobs. Who will employ 30 of them?
This project has many complex parts to consider. They are all critical - all 1000 parts.
There are too many grains of sand on the beach to count them all. At least a million of them are in my left shoe.
Using "a lot of" or "lots of" is sort of personal preference. In most cases the 2 are interchangeable.
There is a lot of ice on the road, so drive carefully! Also, there's lots of snow!
We still have a lot of work to do - lots of separate tasks to complete.
I found a lot of sand in my right shoe, and lots more in places I didn't know existed.
A lot of people make the mistake of writing "alot," so don't do that!
In most cases either one works fine, but you should be careful about replacing "a lot" or "lots" with "many" or "much." Note that in the examples below "many" works in place of "lots/a lot", but "much" doesn't work at all.
At first there was just one monkey, but then the banana truck exploded and there were lots of monkeys running all over the place!
A lot of the monkeys ran off to the beach afterward. Lots of bananas still litter the road though.
The town will need to hire a lot of people to clean them up. Lots of people need jobs now anyway.
In many contexts, the meanings are pretty much the same, but you might hear finished more often than completed in casual conversation. For example:
I've finished my shopping.
She finished the song.
He finished the race.
I could use completed in those sentences – the meaning wouldn't change, but the register might sound off.
The word completed can convey some sense of accomplishment. In the context of a race, it might work when the race is a major achievement:
He completed his first marathon last year.
Homework, though, is not really a major achievement, so I think you'd hear finished more often in casual conversation:
“Joey, where are you going? Did you finish your homework?”
That said, you might see completed in more formal contexts, such as a paper on education, or a course syllabus:
Students must complete six homework assignments during the semester.
Best Answer
We don't use much with an adjective except in the comparative form (like happier). We use it with a noun: I feel much joy. With an adjective, we use an adverb such as very: I feel very happy.
The difference in meaning between I feel very happy and I feel much happier is that the first sentence isn't comparing its state of happiness to any other state. I feel much happier implies that there was some point in the past, or some hypothetical situation, that we are comparing the feeling to. That's why it's called the comparative form.
Consider these sentences:
The first sentence compares the state of happiness to some other point in time. The second sentence compares the state of happiness to a hypothetical situation.