1. [单选题]Each cylinder is closed at the top by a _____, made of a special heat-resistant steel.
A. cylinder liner
B. coupling flange
C. cylinder cover
D. piston crown
2. [单选题]The first requirement for logical troubleshooting of any system is the ability to
A. collect all available data on a casualty
B. recognize normal operation
C. identify the probable cause of a symptom
D. isolate the faulty component
