og中三题，关于介词in的用法，in是可有可无的么
The normative model of strategic decision-making suggests that executives examine a firm's external environment and internal conditions, and in using the set of objective criteria they derive from these analyses, can decide on a strategy.
A.conditions, and in using the set of objective criteria they derive from these analyses, can decide
B.conditions, and they use the set of objective criteria derived from these analyses in deciding
C.conditions and, in using the set of objective criteria derived from these analyses, deciding
D.conditions and, using the set of objective criteria derived from these analyses, decide
E.conditions and, in their use of the set of objective criteria they derive from these analyses, they decide
这里选项A和C都有in，但是og的解释并没有说多了介词in而排出，这里in是可有可无的么？
联想到另一题的未划线部分，In developing new facilities for the incineration of solid wastes,we must avoid the danger of shifting environmental problems from landfills polluting the water to polluting the air with incinerators.
A.landfills polluting the water to polluting the air with incinerators
B.landfills polluting the water to the air being polluted with incinerators
C.the pollution of water by landfills to the pollution of air by incinerators
D.pollution of the water by landfills to incinerators that pollute the air
E.water that is polluted by landfills to incinerators that pollute the air
开头有in，可是去掉in也读的顺，在语法上也没发现错误，这里的in也是可有可无的么？求赐教
In the textbook publishing business, the second quarter is historically weak, because revenues are low and marketing expenses are high as companies prepare for the coming school year.
A.low and marketing expenses are high as companies prepare
B.low and their marketing expenses are high as they prepare
C.low with higher marketing expenses in preparation
D.low, while marketing expenses are higher to prepare
E.low, while their marketing expenses are higher in preparation这题 C选项中的in又代表什么意思呢？
顺便问一句，A中的as是做什么成分修饰什么呢？ |
