知其一，不知其二

Explanation: To know things on the one hand, do not know the other. Describe incomplete knowledge of things. 　　Source: "Book of Little Zong Xiao Ya" Tiger not violence, not Von River, people know these one Mozhi other. " 　　Examples: You only ~, today the road is more dangerous, I lug heavy, really hard to take. ★ Ming Wu Cheng-en, "Journey to the West" back to the 47th