在先的

It seems wise to reconnoiter before entering the town.

进入那城以前, 先侦察一下是明智。

Filter out all the dirt before using the water.

用水以前先将其中不清洁东西过滤掉。

You should gather yourself together firstly under conditions of great danger.

极其危险情况下你应当先控制住自己。

Mary scraped the residue of food from the plates before putting them under water.

玛丽把盘子放入水之前先刮去上物残渣。

There's a special enclosure where you can look at the horses before the race starts.

"这里有一处特备围场,比赛前你以先看看马。"

Xanthone was efficiently synthesized from o-chlorobenzoic acid first by etherization and then by Friedel-Crafts reaction in the presence of aluminium trichloride.

以邻氯苯甲酸为原料,先进行醚,三氯铝作用下进行傅-克反应,简洁、高效合成呫吨酮。

The mechanic explained that they would have to make good the damage to the body of the car before they resprayed it.

修理工解释说，给车重新喷漆之前，他们得先把车身毁坏地方修理好。

The orbiting Discovery crew on the way Sunday to rewire the International Space Station first had to make sure the shuttle's heat shield(heatshield) wasn't damaged during lift-off.

星期日，负责发现号轨道工作人员跟国际空间站接轨前，必须先确定热障起飞时没有损坏。