this instrument should have put its work permit number on the box.
A. Who checked
B. Whoever inspected
C. No matter who examined
D. Those who estimates
网友回答
A. Who checked
(答案→)B. Whoever inspected
C. No matter who examined
D. Those who estimates
解析：whoever引导主语从句，失去疑问含义，表示强调无论谁；谁……谁就……等于 anyone who；而who引导名词性从句时， who保留疑问含义谁。