zhǐ
只知其一，不知其二
zhī zhī qí yī, bù zhī qí èr
to know only one aspect but not the other; to have incomplete knowledge
在几种棋类中，他只会下象棋。
zài jǐ zhǒng qí lèi zhōng, tā zhǐ huì xià xiàng qí
Among several types of chess games, he only knows how to play Chinese chess
家里只我一个人。
jiā lǐ zhǐ wǒ yí gè rén.
I'm the only one at home.