【正确答案】 D

【答案解析】assuming可作连词，作“假定，假如”讲，同on the assumption that，supposing，例如：Assuming the house is for sale，Would you buy it?假如那座房子出售，你要买吗?concerning作介词，意为“关于”，例如：I enjoyed the great benefit of his instructions concerning the matter．在此问题上他的指教使我受益匪浅。regarding作介词，意为“关于”，例如：A reward was offered for any information regarding the criminal’s whereabouts．提供该罪犯行踪者可得到一笔赏金。ascertaining是动词ascertain的现在分词，动词原型作“探知，发现；确定；调查，查明，断定”讲。同answer，clear up， find out，learn，solve，例如：The police are trying to ascertain what really happened．警方正设法查个水落石出。