A.1.2倍 B.1.3倍 C.1.4倍 D.1.5倍
A.0.35~1.30m; B.0.30~1.40m; C.0.30~1.30m;
A.在進(jìn)入梳齒板前; B.立即; C.經(jīng)兩個(gè)梯級(jí)后。