A.環(huán)境改良劑B.生物制品C.代謝改善和強(qiáng)壯漁藥D.殺蟲(chóng)驅(qū)蟲(chóng)藥
A.繼發(fā)性感染B.主動(dòng)經(jīng)皮感染C.被動(dòng)經(jīng)皮感染D.混合感染
A.2mg/LB.4mg/LC.8mg/LD.20mg/L