曼哈顿语法书里说
Also, as a guessing rule ofthumb, try to steer clear ofthe plural possessive form in answer choices. In roughly 80-90% ofpublicly released problems that contain the plural possessive in the underlined portion, the GMAT avoids the plural possessive answer choice or choices for a variety of reasons:...
书上说 一般情况下 GMAT不喜欢复数所有格