http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Chemistry%20%289701%29/9701_s11_qp_42.pdf
q4ai) and 4bi) how can i know which part is the repeating unit.

Question

http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Chemistry%20%289701%29/9701_s11_qp_42.pdf
q4ai) and 4bi) how can i know which part is the repeating unit.

thadyoung · Answer

Well, it's telling you that the monomer is ethenyl acetate, which you have drawn there. That means that's the repeating unit. 
Not sure if you have covered this, but you also have resonance there which it can easily help to know where it's going to attack (the incoming repeat)
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thadyoung · Answer

the repeat is the ethyl group.