1、Mary is always polite, but her brother is rude.
2、The weather is hot in summer and cold in winter.
3、The old house is dark and gloomy, but the new one is bright and cheerful.
4、The young girl is quiet, while her sister is loud.
5、The cat is sleeping peacefully, while the dog is barking loudly.
6、The teacher praised the hardworking student, but scolded the lazy one.