54+15=2920(m);
答:这个蓄水池的深度是2920m.
故答案为:2920.
With the world changing fast, we have something new _______with all by ourselves every day.
A.deal
B.dealt
C.to deal
D.dealing
代维人员严格遵守(),并在必要时,使用适当的个人防护用具。