C选项迷惑点在于 正确的应该是Most merchandise orders placed in response to advertisements in systems last year by systems subscribers were over age thirty-five.
而C项通过替换were的位置就使得意思完全不一样
B问题:although其实跟Whereas意思相近,所以没问题。但后面的as competing companies one day may be partners the next, one day变成了be 的状语, 那意思变成是be partner又one day又the next, 意思矛盾。
C选项迷惑点在于 正确的应该是Most merchandise orders placed in response to advertisements in systems last year by systems subscribers were over age thirty-five.
而C项通过替换were的位置就使得意思完全不一样