吴林商店规定，喝完啤酒后，用4个空瓶可换1瓶啤酒，李叔叔买了21瓶啤酒，实际最多可以喝多少瓶啤酒？0b3h'm-?9s0x+]*N4Y'k4},n5V8`
算式：提示;h7X2n.s(d0b3h'm-?9s0x+]*N4Y'k4},n5V8`
答：实际最多可喝2^6d/W1[2w4q(v7?瓶啤酒。0b3h'm-?9s0x+]*N4Y'k4},n5V8`