A.三角形 B.鋸齒形 C.梯形 D.管螺紋
A.長(zhǎng)對(duì)正寬相等高對(duì)齊 B.長(zhǎng)對(duì)正寬相等側(cè)對(duì)齊 C.寬相等高對(duì)正長(zhǎng)相同 D.長(zhǎng)對(duì)正寬平齊高相等
A.1 B.2 C.3 D.4