The two-stroke cycle begins with the piston coming up from the BDC, with the scavenging ports in the sides of the cylinders being （）.

A.the engine stopped
B.the engine was stopped
C.he stopped the engine
D.he had stopped the engine

A.To satisfy
B.To be satisfied
C.After satisfying
D.After being satisfied

A.forces
B.enables
C.makes
D.is able to