A.100B.60C.50D.40
A.1.0,0.7B.0.7,0.3C.0.8,0.5D.0.6,0.7
A.不應(yīng)小于90°B.不應(yīng)大于90°C.不應(yīng)小于120°D.不應(yīng)大于120°