We can use him as a backup if one of the other players drops out.
如果有參賽者退出，我們可以用他作為替補。
You can't have one without the other, as the song says
就像歌裡唱的`那樣，兩者密不可分，不能只取其一。
My three guitars broke one after the other
我的3把吉他陸續都壞了。
Sybil ate three biscuits, one after the other
西比爾接連吃了3塊餅乾。
He looked from one to the other of them, then salaamed and left.
他掃了他們每個人一眼，行了個額手禮就離開了。