练习材料
Lesson 7-2 Bats
Every solid object will reflect a sound, varying according to the size and nature of the object. A shoal of fish will do this. So it is a comparatively simple step from locating the sea bottom to locating a shoal of fish. With experience, and with improved apparatus, it is now possible not only to locate a shoal but to tell if it is herring, cod, or other well-known fish, by the pattern of its echo.
It has been found that certain bats emit squeaks and by receiving the echoes, they can locate and steer clear of obstacles -- or locate flying insects on which they feed. This echo-location in bats is often compared with radar, the principle of which is similar.
/ˈlɛsən/ 7-2 /bæts/
/ˈɛvəri/ /ˈsɑləd/ /ˈɑbʤɛkt/ /wɪl/ /rəˈflɛkt/ /ə/ /saʊnd/, /ˈvɛriɪŋ/ /əˈkɔrdɪŋ/ /tu/ /ðə/ /saɪz/ /ænd/ /ˈneɪʧər/ /ʌv/ /ði/ /ˈɑbʤɛkt/. /ə/ shoal /ʌv/ /fɪʃ/ /wɪl/ /du/ /ðɪs/. /soʊ/ /ɪt/ /ɪz/ /ə/ /kəmˈpɛrətɪvli/ /ˈsɪmpəl/ /stɛp/ /frʌm/ /ˈloʊˌkeɪtɪŋ/ /ðə/ /si/ /ˈbɑtəm/ /tu/ /ˈloʊˌkeɪtɪŋ/ /ə/ shoal /ʌv/ /fɪʃ/. /wɪð/ /ɪkˈspɪriəns/, /ænd/ /wɪð/ /ɪmˈpruvd/ /ˌæpəˈrætəs/, /ɪt/ /ɪz/ /naʊ/ /ˈpɑsəbəl/ /nɑt/ /ˈoʊnli/ /tu/ /ˈloʊˌkeɪt/ /ə/ shoal /bʌt/ /tu/ /tɛl/ /ɪf/ /ɪt/ /ɪz/ /ˈhɛrɪŋ/, /kɑd/, /ɔr/ /ˈʌðər/ /wɛl/-/noʊn/ /fɪʃ/, /baɪ/ /ðə/ /ˈpætərn/ /ʌv/ /ɪts/ /ˈɛkoʊ/.
/ɪt/ /hæz/ /bɪn/ /faʊnd/ /ðæt/ /ˈsɜrtən/ /bæts/ /ɪˈmɪt/ /skwiks/ /ænd/ /baɪ/ /rəˈsivɪŋ/ /ði/ /ˈɛkoʊz/, /ðeɪ/ /kæn/ /ˈloʊˌkeɪt/ /ænd/ /stɪr/ /klɪr/ /ʌv/ /ˈɑbstəkəlz/ -- /ɔr/ /ˈloʊˌkeɪt/ /ˈflaɪɪŋ/ /ˈɪnˌsɛkts/ /ɑn/ /wɪʧ/ /ðeɪ/ /fid/. /ðɪs/ /ˈɛkoʊ/-/loʊˈkeɪʃən/ /ɪn/ /bæts/ /ɪz/ /ˈɔfən/ /kəmˈpɛrd/ /wɪð/ /ˈreɪˌdɑr/, /ðə/ /ˈprɪnsəpəl/ /ʌv/ /wɪʧ/ /ɪz/ /ˈsɪmələr/.
