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.

Such a rope is weaker than a hawser-laid rope of equal size, but by reason of its construction it is more elastic and is therefore used where elasticity is the chief requirement, as in towing.
Such a rope

On no account must stage lashing be used for paint ship stages.
 stage lashing

Such a rope is weaker than a hawser-laid rope of equal size, but by reason of its construction it is more elastic and is therefore used where elasticity is the chief requirement, as in towing.

Such a rope