Machines that use hydraulic pressure including elevators, dentist chairs, and automobile brakes.
A.exclude
B.excluding
C.include
D.are included
参考答案:C
解析:结构应用。划线部分应填本句的谓语动词(machines是主语,that use hydraulic pressure是定语);根据句意,谓语动词应表“包括”之意,且在此不表被动,因此选项C是答案。