单选题The two-stroke cycle begins with the piston coming up from the bottom of its stroke, with scavenge ports in the sides of the cylinder being （）.AshutBclosingCopenedDclosed
单选题
The two-stroke cycle begins with the piston coming up from the bottom of its stroke, with scavenge ports in the sides of the cylinder being （）.
A
shut
B
closing
C
opened
D
closed
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