Hi there, can anybody explain the difference between "a great deal of" and "a large number of"...thanks,
Usually "a great deal of" would refer to a singular item, often abstract nouns. It will usually take the singular verb.
"A large number of" refers to many individual items, and usually refers to normal physical items; it will usually take the plural verb.
If you go to Heathrow at the moment with a lot of handbaggage, you will end up with a great deal of trouble.
If you go to LHR at the moment, with a large number of bags, you will end up with a great deal of trouble.
BTW, in British English, I think a "a good deal" is slightly more common than "a great deal", but I might be wrong.