单选题 At last John Smith chose to step down as the company's chief executive and return to his roots in software research.
A. resign B. remove C. retire D. replace

【正确答案】 A
【答案解析】[解析] A项的意思是“辞职”与“step down”在本句表示的“离职”意思相近。B项“移动，搬走”；C项“退休”；D项“代替”。