Explanation:

- The passage speaks about the significance of friendship and how it should be cherished.

- "Blessed is the man or woman into whose life has come the beauty and power of such a _____."

- This line emphasizes the importance of a significant, likely intangible, emotion or relationship.

- "Do all in your _____ to keep such a friendship unbroken."

- This part suggests a considerable effort or action is needed.

- "Avoid the _____, for when it comes it cannot be _____ and the jarring note mars the harmony."

- The passage warns against something negative that can disrupt harmony:

- Option 1: treated - Implies dealing with something; not fitting as the focus is on harmony.

- Option 2: build - Generally means to create or establish; not fitting here.

- Option 3: mended - Suggests fixing something that was broken.

- Option 4: eradicated - Implies complete removal; rarely associated with harmony restoration.

- Correct Answer: mended - "Mended" fits best as it relates to repairing something broken, akin to restoring harmony.

- "It is not alone a question of _____ that may be full and complete."

- Indicates there's more than just an external appearance at stake.

- "It is the hurt in the heart that will not readily heal and the confidence that will not fully come back."

- Shows the impact of broken trust or damage in a relationship.