# to them ... they

All occurrences of "them" and "they" refer to the people in the crowd.

# Though they are seeing, they do not see; and though they are hearing, they do not hear, or understand.

Jesus uses this parallelism to tell and emphasize to the disciples that the crowd refuses to understand God's truth. 

# Though they are seeing

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"

# they do not see

Alternate translation: "they do not understand" 

# though they are hearing

Alternate translation: "Though they are able to hear"

# they do not hear

Alternate translation: "they do not listen well" or "they do not pay attention"