走進(jìn)科學(xué)

Bats use their ears to find their way in the dark（在黑暗中）. They make sounds（發(fā)出聲音） as they fly. When the sounds hit（碰撞） things， they bounce back（反彈回來(lái)） to the bat’s ears. Bats then fly away from those hard（硬的） things.