The parachutelike membranes of Africa's scaly-tailed flying squirrels differ from those of the flying squirrels in the family Sciuridae because they are attached to a cartilage rod at the elbow instead of the wrist.
 | because they are attached to a cartilage rod at the elbow instead of |
| | because of being attached to a cartilage rod at the elbow rather than at |
| | in their attachment to a cartilage rod at the elbow instead of being attached at |
| | in that they are attached to a cartilage rod at the elbow rather than at |
| | in their being attached to a cartilage rod at the elbow instead of |
这道题大家帮忙分析一下每个选项存在的问题好吗？谢谢。我主要没分清instead of 和rather than 的区别。如果A选项，instead of 加上 being at，能是一个正确的选项吗？谢谢