---What time does the library open? eight o’clock.A. InB. OnC. AtD. To

问题补充：

---What time does the library open?

--- eight o’clock.

A. In

B. On

C. At

D. To

答案：

A. In

B. On

(答案→)C. At

D. To

解析：句意：图书馆几点开门？八点。在具体的几点钟用介词at,在具体的某一天用介词on,在年，月份前面用介词in,故选C