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(bǔ)。

　　You can't have one without the other, as the song says

　　就像歌里唱的那樣，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(xù)都壞了。

　　Sybil ate three biscuits, one after the other

　　西比爾接連吃了3塊餅干。

　　He looked from one to the other of them, then salaamed and left.

　　他掃了他們每個(gè)人一眼，行了個(gè)額手禮就離開了。