单选题 From the passage we learn that ______.

A、 dictionaries completely cover the words we can make use of
B、 "schoolroom" is used in the passage as an example of a specialized term
C、 once you know how a word is pronounced and what it represents, you have turned it in-to your active vocabulary
D、 active vocabulary refers to words we understand when we read and hear them

【正确答案】 C

【答案解析】C项与文章最后一句话相符。