▲閱讀下文，回答第 46-50 題Some people scream when they see a five-centimeter-long cockroach. Imagine seeing a flyinginsect with wings 70 centimeters wide! That was the size of the largest known insect, a dragonfly thatlived some 200 million years ago. Today's dragonflies are much smaller, but they may still have awingspan of 18 centimeters. Though most are not that large, they are all highly-attractive insects.Actually, the common name dragonfly refers to two major kinds of insects－dragonflies and damselflies.The former are longer and thicker, resting with their wings outstretched; the smaller damselflies close theirglasslike wings above their backs when resting.Although excellent fliers, dragonflies and damselflies spend most of their life cycle in water.The young hatch from eggs and spend from one to three years at the bottom of streams or ponds.There, they consume nearly anything smaller than themselves, helping to reduce insect pests. In theiradult phase, these insects leave the water in late spring and spend summer flying near their homes,eating large numbers of harmful insects. Dragonflies bear a fearful name because legend used to haveit that they could sting people with their tails. The truth is that they can neither bite nor sting. Becauseof their colorful and shiny appearance, dragonflies are a delightful gift of nature.
46. What is the best title for the passage?
(A) The Oldest-Known Insect
(B) The Differences between Dragonflies and Damselflies
(C) Facts about Dragonflies
(D) Insect Pests: Dragonflies