1. Recent essays by Garrison Keillor, the humorist and host of the public radio show A Prairie Home Companion, describes what might happen if Huns, Goths, and Visigoths were to invade LACE w:st="on">ChicagoLACE>.
(A) describes what might happen if Huns, Goths, and Visigoths were to invade
(B) describes what would happen if Huns, Goths, and Visigoths invaded
(C) describes what would happen if Huns, Goths, and Visigoths would have invaded
(D) describe what might happen if Huns, Goths, and Visigoths were to invade（D）
(E) describe what happen if Huns, Goths, and Visigoths invade
怎么答案是D呢? GMAT中不是不能出现be to do 结构的吗? | 
