[求助]GMATPREP的一道～困惑～语法题 - ChaseDream

Scientists believe that unlike the males of most species of moth, the male whistling moths of Nambung, Australia, call female moths to them by the use of acoustical signals, but not olfactory ones, and they attract their mates during the day, rather than at night.
a) by the use of acoustical signals, but not olfactory ones, and they attract
b) by the use of acoustical signals instead of using olfactory ones, and attracting
c) by using acoustical signals, not using olfactory ones, and by attracting
d) using acoustical signals, rather than olfactory ones, and attract
e) using acoustical signals, but not olfactory ones, and attracting

标准答案是d。
但我觉得d的前面还缺少一个by，否则句子结构不完整。大家觉得呢？

d) using acoustical signals, rather than olfactory ones, and attract
注意优先使用rather than 和谓语平行结构,by using and using both are accepted,都是表行为方式状语.

以下是引用lkl4008在2006-4-11 19:06:00的发言：

d) using acoustical signals, rather than olfactory ones, and attract
注意优先使用rather than 和谓语平行结构,by using and using both are accepted,都是表行为方式状语.

比如：
I play games using computer.
I call him using telephone.
I eat using 筷子.
I breathe using nose.
I watch using eyes.
I walk using feet.
I take GMAT using my mind.
。。。
这样的结构总觉得很怪，但又有点无可奈何。。。而且毕竟，D比其他选项更好一点。

以下是引用lkl4008在2006-4-11 19:06:00的发言：

d) using acoustical signals, rather than olfactory ones, and attract
注意优先使用rather than 和谓语平行结构,by using and using both are accepted,都是表行为方式状语.

比如：
I play games using computer.
I call him using telephone.
I breathe using nose.
I watch using eyes.
I walk using feet.
I take GMAT using my mind.
。。。
感觉这样的结构好怪，但又有点无可奈何。。。而且，毕竟D比其他选项更好一点。