根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。
Eye strain is a very common problem. Whether it is from working on a computer, watching TV, driving or any number of other activities, your eyes can become tired and lose focus.___ With that in mind, here are 4 simple tips to help prevent eye strain.
1. Take breaks.
The best way to prevent eye strain is using them not too much. Your eyes use more than one set of muscle. That means you can relax one set while using another. ____ If you are at your computer, look out the window for a minute. If you are driving, check your speedometer every so often.
2. Reduce glare.
Reducing glare will certainly reduced the strain on your eyes. Use non-reflective interfaces(界面) whenever possible. _____ When you have to use a screen make sure is at a 90 degree angle from any direct light source.
3. Adjust contrast.
Ensure there is good contrast with what you are looking at. More contrast makes edges easier to recognize so the eyes don’t have to focus as much. ____ Keep overall lighting levels at a moderate level so there is good contrast around you but glare does not become a problem.
4. ___
Eye stain is actually the strain of the muscles controlling the eyes. Strengthening these muscles with a series of eye exercises will prevent eye strain effectively.

A．Strengthen your eyes.

B．Build up the muscles by sleeping.

C．Sunlight makes things easier to see.

D．Change your focus from near to far on a regular basis.

E. But too much contrast with the surrounding area will cause strain.
F. For example, reading from paper instead of a computer screen.
G. Serious eye strain can cause a number of other problems such as near-sightedness.