MIMD systems can be classified into (71) -oriented systems, high-availability systems and response-oriented systems. The goal of (71) . oriented multiprocessing is to obtain high (71) (72) minimal computing cost. The techniques employed by multiprocessor operating systems to achieve this goal take advantage of an inherent processing versus input/output balance in the workload to produce (73) and (74) loading of system (75) .

（71）处填（）。

A．though

B．through

C．throughout

D．throughput

一般用于航空工业，可做弹簧、齿轮、蜗轮、蜗杆等耐蚀和耐磨零件的青铜为( )。

A．锡青铜

B．硅青铜

C．铍青铜

D．铝青铜