10. Climatic shifts are so gradual as to be indistinguishable at first from ------------------------------------------------ ordinary fluctuations in the weather. (A) so gradual as to be indistinguishable (B) so gradual they can be indistinguishable (C) so gradual that they are unable to be distinguished (D) gradual enough not to be distinguishable (E) gradual enough so that one cannot distinguish them
so....that 和so.......as to均表示 很......以致.......。so.......as to 后面的动词的逻辑主语和主句的一致。如此例及OG的88题。so....that.....,that后面接从句,主语可与主句的不一致,如She was so young that you must excuse her。 此句选A 而不选C的问题主要在SO。。。。THAT 和are unable to 连用不好。 个人理解。