1£®(2020·È«¹ú¾í¢ñ)The engineers are also trying to develop an on and off “switch” where the glow would fade when exposed to daylight.                                                                                   ±ä°µ

2£®(2020·½­ËÕ¾í)Adapted in imaginative ways, many have reappeared on city streets and village greens housing tiny cafes, cellphone repair shops or even defibrillator machines.         ¸ÄÔì