Actually , The Gnome 3 is more like IPhone or Android.^_^
The method using the Chinese input method:
1. Activities->Applications->Other->Input Method Selector, click it .
2. Click the link after Use IBus , choose the tab of Input Method
3. Choose the Chinese in the pull menu of +Show all input method , Then you can see the Chinese input method;
4. Choose “拼 Pinyin” for example，then click the right Add button, after all of this you can use Alt+Shift to change to the next input method.
Additional: If you can not find the IBUS components, YOU should install it fisrst.
STEPS:
sudo yum install ibus
sudo yum install ibus-sunpinyin
Good Luck.