n.哨兵；傳送器；[計]標(biāo)記符號
v.放哨；設(shè)崗哨
The sentinel was stationed on a hill. 哨兵被派在山上站崗。
The press is a sentinel of our liberty. 新聞界是捍衛(wèi)我們自由的衛(wèi)兵。
At either end of the bridge a sentinel stood with rifle at ready. 橋的兩頭各有一名哨兵，荷槍實彈守衛(wèi)著。
