how can I mirror in Keynote using IOS7 in my IPAD

Make sure the AppleTV is on, and connected to the HDTV it’s connected to.

Tap Keynote to launch it on the iPad, and then open the presentation you want to give.

To use AirPlay Mirroring, you will need the following:

• iPhone 4S (or later), iPad 2 (or later), iPad mini, or iPod touch (5th generation)
• Apple TV (2nd or 3rd generation)
• Wi-Fi (802.11a/g/n) network

To enable AirPlay Mirroring on your iOS 7 device:

1. Connect your iOS device and your Apple TV to the same Wi-Fi network.
2. Swipe up from the bottom of your screen to access Control Center.
3. Tap AirPlay. You should now see available Apple TVs.
4. Tap the name of the Apple TV you wish to AirPlay to, then tap Mirroring.
5. Once enabled, your iOS device's screen will be mirrored on your Apple TV.

http://support.apple.com/kb/HT5209?viewlocale=en_US&locale=en_US

Hope this helps. Happy Presenting!