A.硬木材 B.軟木材 C.剛性木材 D.柔性木材
A.針葉樹(shù)的樹(shù)葉細(xì)長(zhǎng)呈針狀,樹(shù)干通直高大,紋理順直,材質(zhì)均勻,木質(zhì)較軟且易于加工 B.闊葉樹(shù)的多數(shù)樹(shù)種樹(shù)葉寬大呈片狀,多為落葉樹(shù),樹(shù)干通直部分較短,材質(zhì)堅(jiān)硬 C.闊葉樹(shù)材一般較重,強(qiáng)度高,脹縮和翹曲變形大,易開(kāi)裂 D.水曲柳是典型的針葉樹(shù)
A.1℃ B.2℃ C.3℃ D.4℃