Please choose the correct ending to complete the given sentence: Health: [header] How to prevent neck pain [title] Practice good posture. [step] It doesn't matter whether you're in a chair or standing up, you should still have good posture. Your ears should be directly over your shoulders.

Ending1: In addition, your hips should be in direct alignment with your shoulders, meaning you need to stand up straighter if they're not. Adjusting your posture can help reduce neck pain over time. Ending2: As you're sitting, your upper knees should be more bent than they would be in an upright position, even if your toes are touching. [substeps] Many people feel their shoulders vibrate without consciously acknowledging it. Ending3: When you're comfortable, try to lean back on your feet so you'll be further down in your chair. [substeps] If your head is tilted to one side, try not to lean too far, or it might become uncomfortable. Ending4: Imagine that your ear is the size of a pencil and feel it lay flat against your shoulders. Don't force your shoulders back in any way.

Answer format: ending1/ending2/ending3/ending4