Ответ:

183

a) trousers, spectacles, hair, scissors, glasses, contents, tongs

b) phonetics, optics, knowledge, advice, mathematics

184

Tooth-teeth, mouse-mice, foot-feet, sheep-sheep, news (uncountable), furniture(uncountable), weather (uncountable), louse-lice, roof-roofs, potato-potatoes, man-men

185

Clothes (always plural), pyjamas (alway plural), wives-wife, leaves-leaf, women-woman, pianos-piano, keys-key, shelves-shelf, schools-school, scissors(always plural) valleys-valley, children-child