A.放出2.5cm B.放出2cm C.收進(jìn)1cm D.收進(jìn)2cm
A.B/5 cm B.B/5+0.6cm C.B/5-1cm D.B/5-0.6cm
A.15:2 B.15:2.5 C.15:3 D.15:3.5