Title: Boston.
Question: The Boston Public Library is located in what part of Boston?

Title: Light-emitting diode.
Question: What does the multi-color white LED method need to produce the end result?

Title: Pacific War.
Question: What American carrier joined the USS Yorktown to stop the Japanese attack on Port Moresby in 1942?

Title: Nanjing.
Question:
How long was Nanjing the capital of the Southern dynasties?