Could you tell me whether to use a plural or singular verb in the following sentence?
What I like best about living in Japan is/are its beautiful building.

Could I say:

What I like best about living in Japan is that there are beautiful building.

Question

Could you tell me whether to use a plural or singular verb in the following sentence?
What I like best about living in Japan is/are its beautiful building.

Could I say:

What I like best about living in Japan is that there are beautiful building.

Answer

Elyastam's answers are all correct. The reason you use the singular verb is because it refers to the ONE thing you like best. If you said, "the things I like best," then you would use "are" instead of "is."  And "building" should be plural ("buildings").

Answer

should be:

What I like best about living in Japan is its beautiful buildings.

or

What I like best about living in Japan is seeing its beautiful buildings.

or

What I like best about living in Japan is it has so many beautiful buildings.