Please choose the correct ending to complete the given sentence: Health: [header] How to prevent motion sickness [title] Look out the window frequently. [step] Look at a stable object, such as the horizon. The visual cues of movement will enable your brain to synchronize the visual and physical cues of the swaying vehicle.

Ending1: [substeps] If you are in a car, focusing on an object that is too close for you to clearly see, like trees by the side of the road, may make you feel worse. If you can't see the horizon (you are on a winding road, etc. Ending2: If they look strange, turn your head down and close your eyes. You will use the visual cues to guide your movements in order to control them. Ending3: This is especially helpful when driving a car whose rotation will cause passengers to unconsciously mirror their driving. This will also allow the driver to be aware of which direction the vehicle is going. Ending4: This will provide important practical cues for you to recognize when the vehicle is approaching. If it is not moving smoothly, then it is more likely that it is trying to move.

Answer format: ending1/ending2/ending3/ending4