Identify the sentence that uses a colon correctly.
Correct: C
A colon is correctly used to introduce an explanation or elaboration that directly follows a complete independent clause. In option C, 'We learned an important lesson today' is an independent clause, and the colon introduces the explanation of that lesson. Options A and B incorrectly place a colon immediately after a verb, interrupting the natural flow. Option D uses a colon after 'namely,' which is often redundant as 'namely' itself serves to introduce the list.