A.數(shù)量用多些; B.數(shù)量用少些; C.標(biāo)號(hào)高些; D.標(biāo)號(hào)低些
A.光滑; B.平整; C.粗糙; D.堅(jiān)硬
A.上邊緣; B.下邊緣; C.上下邊緣; D.接頭處