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Intro
Overview
Different Uses Over Time
Pilotage
Environmental Issues
Lock Quiz - 1/5
Intro
Overview
Overcoming Obstacles
Lock Quiz
Question 1
Question 1 : A cargo ship headed downstream arrives at the upper gates of the lock. What should you do?
A - Open the upper gates.
B - Open the emptying valves.
C - Open the filling valves.
D - Open the lower gates
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