Jesus uses this parallelism to tell and emphasize to the disciples that the crowd refuses to understand God's truth. (See: [[rc://en/ta/man/jit/figs-parallelism]])
These words could refer to 1) them seeing what Jesus does. Alternate translation: "Though they see what I do" or 2) their ability to see with their eyes. Alternate translation: "Though they are able to see"
These words could refer to 1) them hearing what Jesus teaches. Alternate translation: "Though they hear what I say" or 2) their ability to hear with their ears. Alternate translation: "Though they are able to hear"
Here "hear" represents listening well. Alternate translation: "they do not listen well" or "they do not pay attention" (See: [[rc://en/ta/man/jit/figs-metaphor]])