有9米长的绳子,第一次用去3米,第二次用去3米,还剩请选择BA7f,?:u/h.P0Z9v'X,m,Z(r5h2l7p0K0[0W1d4X+g1]
A.9-3-3=3(米),Z(r5h2l7p0K0[0W1d4X+g1]
B.3+3=6(米),Z(r5h2l7p0K0[0W1d4X+g1]