下列試題詞語中加點的字，讀音全都正確的一組是
為改善環境，某城市對污水處理系統進行改造。三年后，城市污水排放量由原來每年排放 125 萬噸降到 27 萬噸，那么污水排放量平均每年降低的百分率是（）
— The manager of the factory wants to improve production a great deal, but he doesn’t spend much on technology.
— I am afraid he won ’t realize his dream. You know ________.
—I can't remember those grammar rules!
—__________. Practice more.
以下屬于環境反饋作用的是：()
