took him two months building/to build a house

Question

Are the following sentences both okay? If so, what's the difference?

It took him two months to build a house.

It took him two months building a house.

Answer 1

Only the first sentence is correct. The correct syntax for expressing that (A) is necessary for (B) (for someone) is

It takes (someone) (A) to (do B).

For example, you could say "It takes three eggs to make an omelette."

If you write it as "two months building a house," this essentially functions as a single noun phrase, and that makes it sound like the whole phrase is just part (A). You could use the whole thing as a part (A) if you had a part (B) - for example,

"It took him two months building a house to realize that he isn't good at building houses."

But it doesn't work if you just write "It took him two months building a house" by itself.