Taiwan's blue sand or blue tear is a phenomenon ＿＿（38）＿＿ along the coasts of Taiwan's outlying islands caused by sea sparkle that lives under the sea. As indicated by the name of the species, it is known as a sea firefly that will ＿＿（39）＿＿ a light when being disturbed. These sea fireflies like to gather along the coast because it provides them with a rich source of food supply. And when they gather and produce lights from their bodies, they can really ＿＿（40）＿＿ the tides into different colors such as red, green, or blue. For instance, the blue sand or blue tear phenomenon can be seen in many places around the world. In Taiwan, it can be viewed in Kenting, the coast lines in Hualien and Taitung ＿＿（41）＿＿ on several outlying islands. The most widespread blue sand so far has been spotted on Mazu islands in April 2014. The best season to visit the sight is in late spring and early summer, between April and May, but its occurrence will also ＿＿（42）＿＿ the wind. As narrated by one of the witnesses, one of the signs for the appearance of the blue sand is that the sea will start to turn dark a few days before it actually happens. No matter what it is, seeing the sight of blue sand is really one of the rare moments in our life.