单选题The four-stroke cycle begins with the piston （）.Acoming up from the BDCBcoming up from the TDCCcoming down from the BDCDcoming down from the TDC
单选题
The four-stroke cycle begins with the piston （）.
A
coming up from the BDC
B
coming up from the TDC
C
coming down from the BDC
D
coming down from the TDC
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