A.地徑的2-4倍B.地徑的4-6倍C.地徑的6-8倍D.地徑的8-10倍
A.點(diǎn)播B.條播C.撒播D.混播
A.20~40cm,10~20cmB.30~60cm,20~40cmC.30~50cm,20~30cmD.40~70cm,30~50cm