A.2mm B.10mm C.15mm D.20mm
A.100° B.120° C.165° D.200°
A.A=0,且B≤1,且B+C≤4 B.A=0,且B≤2,且B+C≤4 C.A=1,且B≤1,且B+C≤4 D.A=1,且B≤1,且B+C≤3
A.15 B.20 C.25 D.45
A.1/2 B.1/3 C.1/4 D.1/5