Question

place the missing punctuation into the sentence. if the sentence is correct, leave it as is.
when the beautiful new science building was completed, i felt like all the years of fundraising were worth it.

Explanation:

The sentence "When the beautiful new science building was completed, I felt like all the years of fundraising were worth it." is already correctly punctuated with a comma after the dependent clause and a period at the end. So no additional punctuation is needed.

Answer:

The sentence is correct as is: "When the beautiful new science building was completed, I felt like all the years of fundraising were worth it."