单选题 The chief executive officer is particularly ______ that recent staff surveys have shown a severe drop-off in employee satisfaction.

【正确答案】 D
【答案解析】concern既可作及物动词，表示“使担心，使忧虑”，又可作名词表示“关心；忧虑”的名词。concerning虽然词形像现在分词，其实是表示“关于，涉及”的介词。concerned表示“关心的，有关的”，一般用于be concerned about/for/with sth.或be concerned+that从句。