You can move multiple questions from one Question Bank to another.
In Course Navigation, click the Quizzes link.
Manage Question Banks
Click the Settings icon  and click the Manage Question Banks link .
Open Question Bank
Open the Question Bank by clicking the title of the Question Bank.
Click the Move Questions button.
Select questions to move  and select the destination bank . Then click the Move Questions button to move the questions to the selected bank.
You can also select the option to Keep a copy in this question bank .