[填空题]
A bat emits a series of high frequency sohw8 b4u,mw*mkund pulses as gg)v24sc q)n eit approaches a moth. The pulses are approximately 70.0 ms apart, and each is about 3.0 ms long. How far away can the moth 4)2vn )qge scgbe detected by the bat so that the echo from one chirp returns before the next chirp is emitted? m
