The sun is setting on a summer night． At the entrance to a deep, dark cave, a few bats fly out and begin swirling high up into the air．More and more of the small, furry creatures appear．Within a few minutes, a whole river of bats is pouring out of the cave, and they keep coming, millions and millions of them．

       Sound like a scary horror movie? Believe it or not, this scene takes place every night, all summer long, at Bracken Cave in Texas, where 20 million bats fly outside to feed on insects．"It is magical," says Jim Kennedy of Bat Conservation International in Austin Texas．"It is one of the most majestic（壮丽的）  animal movements on the planet．"

       Every March or April, Mexican Free-tailed bats migrate up to 1,000 miles （1609 kilometers） from their winter home in Mexico to this cave, where they raise their young．Soon after they arrive, each mother gives birth to one pup．As many as 500 baby bats live crammed into one square foot （30．48 cubic centimeters）of space, and all those bodies create nice warm temperatures to keep them cozy and comfortable．If you've ever lost sight of your parents on a crowded playground, you may be wondering how mother bats recognize their children．They use their sense of smell to tell which pup is theirs when it is．time for the babies to nurse．

       The cave, a quiet place in winter, is full with life all summer-and not just with bat residents．Bat waste soon covers the floor, providing food for tiny organisms（生物体） like bacteria and fungi（真菌类）．And then there are the bugs．

       When the adult bats leave the cave at night to feed, they are helping humans．They eat tons of insects in a single night, including many pests that eat farmer's crops． And they get rid of mosquitoes, too． 

66．In the first paragraph, the author          .

       A．provides some information about bats         B．describes the movement of bats

       C．advises the reader to watch bats          D．stresses the danger of bats in summer

67．By saying “Sound like a scary horror movie?” what does the author mean?

       A．Bats are better horrible characters in films．  B．People tend to feel afraid of bats．

       C．The above scene is somewhat unbelievable．D． The cave mentioned is full of adventure．

68．According to the passage, the reader possibly expects that           ．

       A．no people know how many bats live in Bracken Cave．

       B．a bat mother would have trouble finding her own baby．

       C．bat waste causes much harm to the human environment．

       D．farmers will never have a good harvest without the bats．

69．Which of the following is TRUE about the bats?

       A．They are well protected by farmers．

       C．They benefit from some tiny organisms．

       B．They smell better than other animals．

       D．They travel from Mexico to America yearly．

70．From the second paragraph, we can know Kennedy's opinion of the bat's flying in group is        .

       A．mysterious         B．frightful             C．crazy               D．enjoyable