Most idiomatical expressions in Chinese language are greatly related to Chinese culture. Therefore, the learners should know more expressions when they study Chinese. One of the common heard is 白脸儿狼, meaning the wolf with white wolf. When we use this expression, we usually describe the people that are ungrateful, carrying the negative meaning. When foreign students study Chinese, they may often hear 我当初真是瞎了眼，没看出来他竟然是这么个白脸儿狼.

If the aged people use it to describe their grandchildren, it carries the meaning of blaming. One thing the foreign students should know when studying Chinese in China is the origin. It is said that Mr. Dongguo went out and met a wolf being hunted. After the wolf’s begging, he put it into his bag. When they hunter gone, he freed the wolf but the wolf intended to Mr. Dongguo. A farmer came by to judge right or wrong by asking the wolf enter the bag again. Then it was killed by the farmer in the bag. From this story, the foreigners who study Chinese can understand this expression better. we can also say 白眼儿狼.