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.

[Q]: Were this not done, laying the strands together would tend to untwist the yarns in each strand.
[A]: this


[Q]: It should therefore be examined frequently for signs of deterioration.
[A]: It


[Q]: The strands tend to unlay unless the end of the rope is whipped (i,e, firmly bound) with twine.
[A]:
The strands