207. 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 请问答案Ａ中的ＡＳ　是什么意思，怎么试图翻译，可就是说不同呀～！

另一个问题是：不是两个独立的句子要是用ＡＮＤ　连接的话不是之前要加逗号的吗？否则不就是ＲＵＮ－ＯＮ　ＳＥＮＴＥＮＣＥ吗？那么本句怎么就对了？