At this moment, a certain <e1>amount</e1> of chlorine gas was placed inside a <e2>cylinder</e2> with a movable piston at one end.
At this moment, a
At this moment, a certain amount of chlorine gas was placed inside a cylinder with a movable piston at one end.
<triplet> amount <subject> cylinder <object> Entity-Destination(e1,e2)