单项选择题A．He was very slow in doing things.B．He was the right person to do such a thing.C．He is expected to do such a thing.D．He would never do such a thing.

单项选择题A．Mark doesn’t like water.B．Mark doesn’t belong here.C．Mark is like a fish.D．Mark is in this class.

单项选择题A．On short trips.B．On long trips.C．When flying over cities.D．When flying at high altitude.

单项选择题A．They defend the bone against viruses.B．They break down bone tissue.C．They prevent oxygen from entering the bone. D) They connect the bone to muscle tissue.

单项选择题A．People’s health.B．People’s lives and futures.C．The end of the world.D．The Great Depression of 1929.