Some investigations show that the cause of the accident may be the car engine's__.a.fail to operateb.failure to operatec.fail in operation选哪个?为什么?

以下这道题``选哪个?We must make some investigations we can draw any conclusion.We must make some investigations we can draw any conclusion.A.sinceB.beforeC.untilD.when Some investigations show that the cause of the accident may be the car engine's__.a.fail to operateb.failure to operatec.fail in operation选哪个?为什么? Some investigations show that the cause of the accident may be the car engine's__.a.fail to operate b.failure to operate c.fail in operation 答案说选b,WHY? 翻译：Results of accident investigations and recommendations for actions to minimize the risk of 谢 帮忙看下这句话有没有语病However,the prior studies haven’t conducted investigations intothis topic. some some some some some some Some some some some some some Some