What is the difference between big and great?
For example:
"The government has spent a big deal of money attempting to help the region."
Can I use "great" in this sentence?
And for the below sentence:
"I don't really care about failing the exam. It's no great deal, really.
Can I use "big" in this sentence? If no why not?
"It was time for her to make the big or great decision should she agree to marry him?"
Which one is correct? "great or big" ?
The government has spent a great deal of money attempting to help the region.
is the best sounding choice to me. Probably context has a lot to do with it.
For example, big is better here:
I don't really care about failing the exam. It's no big deal, really.
And the last example (including a different grammar correction):
It was time for her to make the big decision. Should she agree to marry him?
or
It was time for her to make the big decision should she agree to marry him.
But in another context:
You made a lot of money. That was a great decision.
In these kinds of examples, great refers to something very positive or beneficial (or very negative or disasterous), while "big" has more to do with the importance of something (as in the marriage decision).
Hmmm - this is a good question, and it's not easy to describe a concrete rule for it...
To start with let's address your 3 examples, which are the opposite of what they probably should be.
"The government has spent a great deal of money attempting to help the region."
A "big deal" is a colloquial phrase referring to something considered very important or noteworthy. Because of this, "big deal" sounds awkward here. What this sentence needs is an adjective to describe "the relative amount of money." A "large amount" of money is another alternative.
"I don't really care about failing the exam. It's no big deal, really.
This is the inverse situation. Here failing the exam is not seen as important or noteworthy, and is therefore "not a big deal."
You could, however, say "It's no great loss," where "great" describes the relative degree or amount of the loss. "Not a big deal" describes the relative importance of the test.
"It was time for her to make the big decision about whether she should agree to marry him."
Getting married is a BIG decision - it's a big deal. It's important and noteworthy. It needs to be given a great deal (a relatively large degree) of consideration.
I would note that the thing being described doesn't have to be a positive thing - it could be a great loss, a great catastrophe, great suffering, etc. Those all describe the relative degree of the thing. However, a sports team could also suffer "a big loss" if they lose a very important game.
