先在的

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

在极危险的情况下你应当控制住自己。

It seems wise to reconnoiter before entering the town.

在进入那城以前, 侦察一下是明智的。

Filter out all the dirt before using the water.

在用水以前中不清洁的东西过滤掉。

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

玛丽在把盘子放入水之前刮去上面的食物残渣。

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

"这里有一处特备的围场,在比赛前你以看看马。"

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,进行醚化,再在三氯化铝的作用下进行傅-克反应,简洁、高效的合成呫吨酮。

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

解释说，在给车重新喷漆之前，他们得把车身毁坏的地方好。

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，负责发现号轨道的作人员在跟国际空间站接轨前，必须确定热障在起飞时没有损坏。