You can post some tweets directly to twitter without writing on both. You can write on the facebook wall which will automatically post on the twitter wall.You have to do these following tips.By doing so you can save the time in today's rushing world.

These are the following steps required.

• Open your browser and log in to your FB account.
• Open a second browser and log in to your Twitter account.
• https://www.facebook.com/twitter/  click on this link and check whether its directly connecting to what you are looking.
• Edit some settings you wish to change(e.g.status,photos,events).
• Click on the link to twitter bitton

This will automatically post your facebook posts to twitter.