阅读下面材料,在空白处填入适当的内容(不多于3个单词)或括号内单词的正确形式。
It’s spring again, and it’s the season of fireflies (萤火虫). Their warm and gentle lights glitter in the quiet        (dark), especially in mountainous areas or near water. No matter      you are, or how old you are, you’re sure to fall under their spell.
For many older people, fireflies are a reminder of childhood. That’s because they were a lot        common long ago,        the industrial development destroyed so much firefly habitat. Wetlands      (appear) and chemicals were dumped into rivers. Fireflies were left with         to feed or breed. What’s more, fireflies seem to keep away      artificial lights. As these spread, the bugs retreated. Not until they had almost vanished        (do) people realize what was happening.
Over the past few years, though, conservation groups and enthusiastic firefly lovers have come together to save these special creatures,       are making a comeback. In natural settings all around the island, fireflies are once again lighting up the night and     (help) create special memories for the next generation.