A.2%~3% B.3%~5% C.1%~5%
A.應(yīng)涂潤滑油 B.應(yīng)涂導(dǎo)電膏 C.應(yīng)涂防塵油 D.不涂任何油質(zhì)
A.不超過2% B.不超過4% C.不超過5%