How do I eject the cd I imported to my computer

Five ways to eject a stuck CD or DVD from the optical drive

Ejecting the stuck disc can usually be done in one of the following ways:

1. Restart the computer and after the chime press and hold down the left mouse button until the disc ejects.
2. Press the Eject button on your keyboard.
3. Click on the Eject button in the menubar.
4. Press COMMAND-E.
5. If none of the above work try this:

Open the Terminal application in your Utilities' folder. At the prompt enter or paste the following:

     usr/bin/drutil eject

If this fails then try this:

Boot the computer into Single-user Mode. At the prompt enter the same command as above. To restart the computer enter "reboot" at the prompt without quotes.

Have a look at Quick Tip: How to Force Eject a Stuck Disc or The ultimate guide to ejecting a stuck disc from Mac SuperDrive.