A.一級(jí)維護(hù) B.日常維護(hù) C.二級(jí)維護(hù) D.三級(jí)維護(hù)
A.效率高 B.經(jīng)濟(jì)性差 C.結(jié)構(gòu)復(fù)雜 D.自動(dòng)適應(yīng)性能好
A.20° B.10° C.15° D.30°