难题-补充材料 262;270

littlebluesk

262 Sunspots, vortices of gas associated with strong electro-magnetic activity, are visible as dark spots on the surface of the Sun but have never been sighted on the Sun’s poles or equator.
(A) are visible as dark spots on the surface of the Sun but have never been sighted on
(B) are visible as dark spots that never have been sighted on the surface of the Sun
(C) appear on the surface of the Sun as dark spots although never sighted at
(D) appear as dark spots on the surface of the Sun, although never having been sighted at
(E) appear as dark spots on the Sun’s surface, which have never been sighted on

选c,a为什么不对?

270 The Olympic Games helped to keep peace among the pugnacious states of the Greek world in that a sacred truce was proclaimed during the festival’s month.
(A) world in that a sacred truce was proclaimed during the festival’s month
(B) world, proclaiming a sacred truce 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
(E) world by proclamation of a sacred truce that was for the month of the festival
选c,为什么用when从句,似乎不和逻辑,
A 不可以么?

NNs, help please!

gemj

262 A中的介词就不对，表达在某个点的概念时用AT而不用ON。