英语改复数step-son step-mother step-brothersister-in-law parent-i

step-son step-mother step-brother
sister-in-law parent-in-law 在 son mother brother sister parent 上加复数 sons mothers brothers sisters parents；
boots halves mouths heat money cows Egyptians dresses
tennis wood（柴火wood 如果是森林woods）chicken music
homeworks bread blood milk dustmen Englishwomen news advice
cotton knowledge tear cloud mice oxen
不变的都是不可数名词