A.大B.小C.不變D.不確定
A.減小上接點(diǎn)片壓力B.減小下接點(diǎn)片壓力C.增大上接點(diǎn)片壓力D.增大下接點(diǎn)片壓力
A.0.7B.0.8C.1.2D.0.9