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Перекладіть речення, вкажіть стан та час присудка (active or passive)
1) The compression stroke takes place, when both valves are closed.
2) The piston must be connected to a mechanism, which controls it's sliding.

1) The compression stroke takes place(active),       when both valves are closed (passive).2) The piston must be connected (passive) to a mechanism,      which controls (active) it's sliding.