1. buff up

提高;擦亮

仿I'm just trying to buff up my listening skill.

2.canopy                   NOUN

a cover that is fixed or hangs above a bed, seat, etc. as a shelter or decoration （牀、座位等上面的）罩篷，遮篷，罩蓋

a layer of sth that spreads over an area like a roof, especially branches of trees in a forest 頂篷；天篷；（尤指森林裏）天篷似的樹蔭

a roof that is supported on posts and is sometimes also attached at one side to a building （有時與建築的一側相連的）天篷，遮篷

仿We can see the canopy of twinkling stars.

3.Summary

Ron complained to Harry about his detention. Harry also told Ron what he had heard in the Lockhart's office .They have no clue about the sound.