专题限时训练(十九)史地自然型阅读理解(二)(限时：25分钟)AIf you are afraid of the dark，its not a big deal.Its perfectly normal to feel afraid. After all，animals do, too. “Fear matters，”says Karen Warkentin，an ecologist.“Its a good thing，” she adds, “because fear makes you do things that keep you alive.”Like kids，many animals experience fear and they respond to the feeling in variety of ways.A frightened turtle pulls its head and legs inside its shell.A small fish will swim away when a big，hungry fish approaches.Some animals respond to fear in ways you might not expect.The first example is that the fear of being eaten can scare some frogs right out of their eggs. Warkentin made the surprising discovery while studying redeyed tree frogs in Costa Rica.In this species，female frogs attach jellylike clumps(果冻一样的块状物)of their eggs to the undersides of leaves.The leaves hang on branches that dangle(悬挂)over ponds.After they hatch from the eggs，the tadpoles(蝌蚪)then fall into the water，where they eventually grow into adult frogs.Tree frog eggs usually grow for 6 days before hatching.If they sense that a hungry snake is about to attack，however，they can hatch up to 2 days ahead of the schedule. As the snakes are unable to swim，by falling into the water early，the tadpoles can escape.If hatching early helps protect redeyed tree frogs from snakes，you might wonder why their eggs dont always hatch sooner.It turns out that hatching early brings its own danger.Once tadpoles land in the water，hungry fish and other animals like to eat them, too.Staying in their eggs for full 6 days，then，allows frog embryos(胚胎)to grow big and strong.This extra growth improves their chances of surviving in the water.1. It can be inferred from the passage that fears_Ahelp animals grow bigger and strongerBare less common among young animalsChelp animals move a lot to fit the environmentDare more or less important in order for animals to survive2. We are told in the passage that tree frogs_Aface danger both inside their eggs and in the waterBwill grow fast if they fall into the water laterCare surprisingly clever when inside their eggsDstay in their eggs longer if they are frightened3. Why do the tadpoles hatch up to 2 days ahead of the schedule？Because_Athey like falling into the water earlyBthey want to grow into adult frogsCthey sense a hungry snake is about to attackDfrog embryos can grow strong4. What is the best title of the passage?AWhat is fearBWhy do we feel afraid?CYou feel afraid，and animals do, tooDFear is a good thing5. What do you think would be discussed in the following paragraph?AFurther explanations as to why tree frogs hatch ahead of the schedule.BHow the unborn frogs know when a snake is about to attack them.CAnother example of animals that respond to fear in an unexpected way.DHow tree frogs improve their chances of survival before falling into the water.BBesides containing attractive flowers, trees and other plants that beautify the community, ecofriendly rain gardens(雨水花园) are healthy for the environment and the people living and working nearby.A rain garden is not very different from a traditional garden. It is just a far more ecofriendly garden. Usually it is built lower than the ground. Rain gardens make smart use of rain and storm water by temporarily holding water from rain and storms and letting it soak(浸入)slowly into the ground before it runs into streams or enters the public drinking water supply.Thus, a rain garden keeps the water, allowing it to be used as needed by plants in the rain garden, rather than flowing immediately into nearby streams and going unused. The water will soak slowly into the ground within a day or two. This creates an advantage that the rain garden does not allow mosquitoes to breed. This is a simple, attractive, and ecofriendly “green” way to treat storm water.Whats more, planting a rain garden helps reduce pollution and improve the environment. Without using expensive machinery and chemicals, rain gardens remove harmful chemicals in the rainwater and cut down on the amount of pollution reaching streams and rivers by up to 30%.Native plants are recommended for rain gardens because they are more used to the local climate, soil, and water conditions. They may attract local wildlife such as native birds. Water your rain garden immediately after planting and once a week, unless you have had at least an inch of rain during the week. Once native plants establish the necessary root system, they will require little care.Often, local governments and private businesses develop large rain gardens in their yards and in public parks as a way to improve the environment and solve flooding problems. However, you dont need to be a professionally environmental engineer to create a rain garden. As long as youre ecoconscious homeowners, you can help the environment by building sma