1、It is treated with acid before being analysed.對它先用酸處理再進行分析。
2、Think what flower it is before move your mouse on.在你將滑鼠放到花朵上前，請先想一想，這是甚麼花
3、We want to learn what it is before anybody else does.我們想先於別人弄清楚。
We had sailed four days and four nights before saw lands .
我們航行了四天四夜纔看到陸地
