Given the task definition and input, reply with output. 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.

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.

Ropes