(XDF)10-14
Scientists have dated sharp-edged flakes of stone found in the dine-grained sediments of a dry riverbed in the Afar region of E to between 2.52 and 2.60 million years ago, pushing back by more than 150,000 years the earliest date ______ stone tools.
(a) when it is known that humans made (为什么错？)
(e) of humans who were known to make （date of human, 如何理解？）
(XDF)11-2
O college in Ohio was a renegade institution _______ both men and women as students.
(a) at its 1833 founding for deciding to accept
(d) in deciding at its founding in 1833 to accept
这两个选项除了介词in/for之外，还有什么correction的错误？两者有什么区别？
(XDF)12-4
The Olympic Games helps to keep peace among the pugnacious states of the Greek _____ .
(a) world in that a sacred trace was proclaimed during the festival’s month
(c) world when they proclaimed a sacred truce for the festival month
(d) world, for a sacred truce was proclaimed during the month of the festival
问什么c正确？原句中的in that的含义为什么改变为when了？d为什么错误？
