找出划线词在文中所对应的原词Long before the invention of radar,_______ hadresulted ina sophisticated radar-like system.
找出划线词在文中所对应的原词11. Radar is an inaccurate term when referring to bats because __________are not used in their navigation system.
找出划线词在文中所对应的原词Radar and sonar are based on similar ________________.
找出划线词在文中所对应的原词13. The word ‘echolocation’ was first used by someone working as a _______.