【题目】In salute to our national flag, every citizen must stand while focusing their eyes on the rising flag.
A. at ease B. at random C. at attention D. at hand
在线课程【答案】C
【解析】
考查介词短语辨析。A. at ease安逸；B. at random随便地；C. at attention全神贯注；D. at hand在手边。stand at attention“立正”。句意：向国旗致敬时，每位公民必须立正，眼睛注视着升起的国旗。故C选项正确。