You could use a reflective tabletop, a mirror, or other shiny, flat surface. Make sure the glare is noticeable even from about 2 to 3 feet (60 to 90 cm) away. If you need to produce glare, you can turn on overhead lights or shine a flashlight on a reflective surface. You should be able to view the surface through one of the lenses at a time. Depending on the size of the lenses in your sunglasses, you might need to move them a little closer to your face. Your sunglasses should be on an angle at this point, with one of the lenses raised slightly higher than the other. Since sunglasses are polarized in a specific direction, rotating the sunglasses can make the polarization more effective. Depending on how the glare is hitting the surface, you might have to slightly adjust the angle of the glasses to see a noticeable difference. If the sunglasses are polarized, you will notice the glare disappears. When you look through one of the lenses, it should be very dark and you should see little to no glare, but it will still look like the light is shining on the surface. Move the sunglasses to compare your regular eyesight to what you see through the sunglasses a few times if you’re unsure of the effectiveness of the polarization.

How would you rephrase that briefly using Chinese?
找一个反光面，要光线照在上面能产生眩光的那种，比如反光的桌面、镜子或者其他光亮的平面。 把太阳镜放在眼前（离眼睛大约15-20厘米）。 把太阳镜向上旋转60度。 透过镜片检查眩光的强度。