胰蛋白酶仅对精氨酸或赖氨酸的的羧基形成的肽键起作用。
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When the crankshaft rotates 20 revolutions, the camshaft rotates ________ revolutions
A. 5
B. 10
C. 15
D. 20
________connects the piston to the crankshaft.
A. Timing chain
B. Flywheel
C. Spark plug
D. Connecting rod
Most pistons have three rings: ________.
A. two oil rings and one compression ring
B. three compression rings
C. two compression rings and one oil ring
D. three oil rings
________ transform the energy of the expanding gases into mechanical energy.
A. Piston rings
B. Connecting rods
C. Pistons
D. Valves
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