________ the help of experienced career instructors, this type of job-hunting training ________ to be very efficient.
A.By; has provedB.With; has provedC.Under; is provingD.With; is proved在线课程B
解析：
本主题要考查固定搭配的识记及动词的语态。根据help的搭配要求，介词须用with，从而排除选项A、C；动词prove表示事物的性质时，为不及物动词，不用被动形式，于是本题的正确答案为B。