This is because changes in the economy have little effect on the amount of work.

Did the manager consider that amount of work a potential problem?

That is, the amount of work they're able to do.

We did a fair amount of work on the book.

"But they still have a huge amount of work to do."

Clearly an enormous amount of work has been put into the site.

And eight hours later, if you were to stop it, then it's done a certain amount of work.

A few hours later, a small but important amount of work had been done.

And a great amount of work has already been done.

We still have a huge amount of work to do.