A.移密補(bǔ)稀、補(bǔ)種B.間苗、定苗C.補(bǔ)種、移密補(bǔ)稀D.定苗、間苗
A.地面B.地質(zhì)C.土壤D.地層
A.2:8~18B.2:4~6C.2:6~10D.1:2~3