136. Although schistosomiasis is not often fatal, (it is so debilitating that it has become an economic) drain on many developing countries. (A) it is so debilitating that it has become an economic (B) it is of such debilitation, it has become an economical (C) so debilitating is it as to become an economic (D) such is its debilitation, it becomes an economical (E) there is so much debilitation that it has become an economical 答案是a没有问题,只是我不明白为什么这里要用完成时。做大全时,时态我一直晕晕的,最后才敢排出这个语法点。 超级感谢! |