Everyone knows that too much time in the sun can expose you to excessive ultraviolet radiation, which can lead to skin cancers.【C1】______thats not going to stop people from cooking themselves【C2】______the perfect tan. The problem has become an【C3】______: more than 3.5 million skin cancers in over 2 million people diagnosed annually in the U.S. 【C4】______our sun-worshipping ways, scientists and the skin-care industry are working hard to 【C5】______out the safest way to tan. A handful of wearable products have【C6】______made it to market that alert wearers of UV radiation【C7】______—they tell you youre about to【C8】______before you can see it. The simplest might be Smartsun wristband, which alerts wearers of UV overexposure with just a【C9】______of color. It starts【C10】______as yellowish-brown when first exposed to UV rays; when it【C11】______pink, thats the warning to seek【C12】______and slather on sunscreen. If you prefer something a little more【C13】______, try the UVeBand, which vibrates when youve had your share of UV rays. Then theres the JUNE, developed and recently【C14】______by Netatmo. The JUNE has UV sensors built into a fake jewel that connect wirelessly to a smartphone, where an app monitors UV【C15】______in real time, alerting when its time to get out of the sun. It also【C16】______your radiation exposure over time,【C17】______you can see how bad your summer has been for your skin, long term. All of these products are designed to help wearers【C18】______their sun time. But none have been reviewed or【C19】______by any health regulatory body, which raises some【C20】______. 【C1】