The sign is often found in a reading-room or a library.
A. NO PHOTOS
B. KEEP QUIET
C. THIS SIDE UP
D. OPEN
网友回答
A. NO PHOTOS
(答案→)B. KEEP QUIET
C. THIS SIDE UP
D. OPEN
解析：此题重点考查四个短语的区别。NO PHOTOS表示禁止拍照。KEEP QUIET表示保持安静。THIS SIDE UP表示此面向上，OPEN表示开门。根据题意可知选择B。