Spock requests a leave of absence

"Captain, I should like to request a leave of absence on my home planet." Spock said. "On our present course, you can divert to Vulcan, with a loss of but 2.8 light days."
"Spock, what the devil is this all about?" Captain Kirk asked.
"I have made my request, Captain!" Spock said. "All I require from you is that you answer it. Yes or no!"