[填空题]
An ocean fishing boat is drifting j e0iwozc3h +l5ust above a scho5m cbn(dogmr )ps*- j8ol of tuna on a foggy day. Without warning, an engine backfire occurs on another boat 1.0 km away (Fig. 1 rd-spcbm*jn 5mo8)g( 2–33). How much time elapses before the backfire is heard (a) by the fish, s (b) by the fishermen? s
