A.5%-10% B.12%-15% C.15%-20% D.20%-25%
A.80% B.60% C.50% D.30%
A.投入成本大 B.常常與高產(chǎn)標(biāo)準(zhǔn)有矛盾 C.易引起環(huán)境污染 D.易殺滅害蟲的天敵