21. 翻譯：碼頭邊的吊車已可使用。
(A). The shipboard cranes are available.
(B). The dockside cranes are available.
(C). The floating cranes are available.
(D). The overhead cranes are available.

答案：登入後查看
統計： A(4), B(9), C(2), D(0), E(0) #1276237