In this task, you are given a sentence. You must find the primary subject in the supplied sentence. The output must be a sub-sequence in the sentence.
Example: Rope and its Usage
Example solution: Rope
Example explanation: The word 'Rope' is the key subject here, while Usage is a property of Rope.

Problem: Ropes are made from vegetable fibres each of which is only between two and four feet long, and the first process is to comb these fibres out in a long, even ribbon, as shown in an exaggerated form in fig. 6-1.

Solution: Ropes