GB2312, which contains 6,763 characters
GBK, which contains 21,003 characters
GB18030-2000, which contains 27,533 characters
To use the GB2312 character set, press Control-Shift-1.
To use the GBK character set, press Control-Shift-2.
To use the GB18030-2000 character set, press Control-Shift-3.
Because GB18030-2000 is a relatively new standard, support in Wubi for the GB2312 and GBK character sets ensures backward-compatibility with earlier standards. You might prefer to work in the GB2312 or GBK character set because of improved performance and lower repetition rates.