下列采取的措施中，属于在传播过程中防治噪声的是（　　）

A．工厂大部分修建在郊区

B．修建房屋时，多采用中间真空的双层玻璃

C．生产线上的工人戴着耳罩作业

D．汽车加装消声装置

A typical (66) language contains an applicative sub-language which approximates the mathematical abstractions of "timeless" functions applied to "spaceless" values, where the actual operation sequences and use of storage space during expression evaluation are organized behind the (67) . In this setting, values are data structures of low volume, typically a few computer words or less, which means that an illusion of spacelessness can be realized by having (68) results during expression evalution stored at the discretion of the language implementation, and effecting parameter (69) and (70) operations through value copying.

68（）

A．middle

B．intermediate

C．previous

D．final