14. A fish hobbyist needs to replace a certain amount of water in tiieir Ssh tanks periodically, mainly because
(A) the accumulation of ammonia.
(B) tiie accumulation of dirt.
(C) the reduction of oxygen.
(D) the increase in temperature.
(E) the increase in pH.
答案:登入後查看
統計: A(35), B(0), C(6), D(1), E(0) #3223032
統計: A(35), B(0), C(6), D(1), E(0) #3223032