单选题 Barbara ______ in doing it again though she had failed more than a dozen times.
A. consisted B. insisted C. persisted D. assisted

【正确答案】 C
【答案解析】persist意为“坚持”，与介词in搭配。A．consist意为“包括，包含”，与介词。{搭配；B．insist意为“坚持”，与介词。D．搭配；D．assist意为“帮助”，与介词in搭配。