GRE Reading Comprehension: JiJing 352-GRE阅读机经352篇 - C55Z4EHWOSF25X3NJ

According to the passage, the configuration of the target is reported to the echolocating bat by changes in the A. echo spectrum of CF signals B. echo spectrum of FM signals C. direction and velocity of the FM echoes D. delay between transmission and reflection of the CF signals E. relative frequencies of the FM and the CF echoes