You look so tired today.What happened，Jack—I didn’t go to bed ________ 12 o’clock last night because there was too much homework.

26. Some experts and educators agree that difficulties and hardships can ______the best in teenagers.

The police recognized the criminal from his typical facial ________.— a scar on the forehead.

依次填入下列各句横线处的成语，最恰当的一组是（ ）①_______________，有言必践，传送着中国的极大诚意，展示了一个负责任大国的襟怀，赢得了世贸成员和国际舆论的佳评。②出了事故，首先应调查原因。“没有调查就没有发言权”，这是决策的科学化问题。古今之市领导，似乎还在车上，就作出重大决定了。而且_______________，权重如天。③在推销的过程中，应该认真准备，力求表达得精炼准确，_______________ ，以达到最佳效果。

It’s necessary ____ our environment(环境). —I agree with you.