Whereas the honeybee’s stinger is heavily barbed and cannot be retracted from the skin, because the yellow jacket has a comparatively smooth stinger, it is therefore able to be pulled out and used again.
A. because the yellow jacket has a comparatively smooth stinger, it is therefore able to be pulled out and used
B. the comparative smoothness of the yellow jacket’s stinger allows them to pull it out and then can therefore use it
C. the yellow jacket’s stinger is comparatively smooth, and can therefore be pulled out and used
D. in comparison, the yellow jacket’s stinger is smooth, and thus able to be pulled out and used
E. in comparison, the yellow jacket has a smooth stinger, thus allowing it to be pulled out and used
答案是C，我选的是E。
我的问题是：既然C中的and之前有逗号，按照prep语法笔记中的讲解，and之前用逗号分隔就不能和and之前的分句并列、共用主语，而应该主谓齐全(本题情况应在and后补出it)，否则应去掉逗号使and前后并列。(如见prep1_56的解释)
E的allowing做伴随结果状语，it的指代确实可能有歧义(jacket&stinger)，但是prep中有提到代词的就近指代原则，也就是说代词的问题有商量的余地，但是C的问题是句子结构问题，我认为更严重。
请大家指教。
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