ブリヂストン美術館は英語の使い方に注意した方が良い。

I often pass by the Bridgestone Museum of Art. It's near our school at Nihonbashi Station. Their current exhibition is called:

△ Why is it masterwork?
◯ Why is it a masterpiece?

●  masterpiece 【名】名作、最高傑作、絶品、名人芸  (definition from Eijiro on the Web)

The problem is a common one for students.

× I had a lot of works today.
◯ I had a lot of work today.

"Work" as we usually think about it, meaning going to the office and so on, is an uncountable noun. "Work" does have a countable version which is usually used for artistic creations like paintings.

Since the exhibition is talking about art, I think the countable version is more correct, though it's hard for me to say it's wrong. I can say, though, that "masterpiece" is much more common than "masterwork". That's the word I would suggest that you remember.

I studied painting in university, but I never produced a masterpiece. Doing so must be a lot of work. Now I need to get to work on something else, so until next time...

● get to work on （～に）着手する、（～を）始める、（～に）取り掛かる (definition from Eijiro on the Web)