導(dǎo)讀：詞組能有效的幫助大家提高完型和句子的理解與寫作質(zhì)量，為保證大家能夠靈活運用考研重點詞組，社科賽斯李梅老師特配以相應(yīng)的例句，幫助大家更快地獲得更高的分數(shù)。
611. on (one's) guard 警惕，提防；站崗，值班
We must be on (our) guard against hidden enemies.
我們必須警惕暗藏的敵人。
612. on (the) one hand 一方面
On one hand, I'm inheriting a new son-in-law.
一方面，我現(xiàn)在有了一個女婿。
613. on (the/an) average 按平均值，通常
American shares rose, on (the/an) average, by 38%.
美國股票價格平均上漲了38%。
614. on a large/small scale 大/小規(guī)模地
This movement has aroused the masses on a large scale.
這次運動，群眾發(fā)動的面很廣。
He's in business on a small scale.
他做的是小本生意。
615. on account of 由于
The flight was postponed on account of bad weather.
因為天氣惡劣，飛行延期了。
616. on behalf of 代表
He spoke on behalf of all the members of the faculty and staff.
他代表全體教職員工講了話。
617. on board 在船(車/飛機)上
My wife and I were the first to arrive and hopped on board.
我和妻子是最早趕到登船/上車/飛機的。
618. on business 因公
I presume you're here on business.
我想你是來這里出差的。
619. on condition that 如果
You can use the bicycle on condition that you return it tomorrow.
只要你明天歸還，自行車你可以拿去用。
620.on duty 上班，值班
We'll take our turn on duty at 1 p.m.
我們下午一點接班。
