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参考解析：
刷刷题刷刷变学霸
举一反三
【单选题】Passage 3 Questions 11 to 15 are based on the following passage: Scientists in India have invented a new way to produce electricity. Their invention does not get its power from oil, coal or other fuel...
A.
Because bullocks have long been used by Indian people
B.
Because bullocks walk slowly and are easy to control.
C.
Because there are few non-working bullocks in India
D.
Because there is not enough oil in India.
【单选题】与渗碳件相比，渗氮件具有（）。
A.
更高的表面硬度和耐磨性，热稳定性较好
B.
更高的表面硬度和耐磨性，但是热稳定性不好
C.
不高的表面硬度和耐磨性，热稳定性较好
D.
不高的表面硬度和耐磨性，热硬性较好