The Gulf of Mexico (墨西哥湾) is being polluted seriously. That has affected _______ several hundred kinds of sea animals there. [ ]

He must have finished his homework for a long time, _____ he?

We seldom dined out so we could save money _____ cooking our own meals. [ ]

They use the same senses as we do and their feet and hands are similar toours,　　　chimpanzees still have opposable toes and can grasp things with their feet.

The chemical factory is far away in the mountains. It is nearly ____ ride from the city.