A.班組長(zhǎng) B.隊(duì)干 C.隊(duì)長(zhǎng) D.隊(duì)干、班組長(zhǎng)
A.人工 B.機(jī)器 C.絞車 D.倒鏈
A.固定 B.支護(hù) C.放頂 D.支柱