Concerned that he has no special knowledge in bussiness management,Mike plans to gain the necessary skillls by taking a part-time course.
追答因为这个句子的主语 Mike 是 concerned 的逻辑主语。也就是说,句子的伴随状语 Concerned that he has no special knowledge in business management 如果写成完整的句子就是 Mike is concerned that he has no special knowledge in business management.
be concerned:为......担忧。