You can easily move questions from one Question Bank to another.
Click the Quizzes link.
Click the Manage Question Banks button.
Open the Question Bank by clicking the title of the Question Bank.
Click the move/copy question to another bank link to copy the question to another bank.
Click the title of the bank [1] where you would like to copy/move the questions. Click the Keep a copy in this question bank as well checkbox [2] if you only want to copy the question. Then click the Move/Copy Questions button [3] to copy the question.