fail
1.fail用作名词只用在without fail中，作“一定不误地、必定”解，用在命令和允诺句里，如Let me know without fail和I will let you know without fail。不可把fail改作failing或failure。
2.fail用在不定式前面有时作“不成功”解，有时作“不…”解，如He failed to obtain the information he had applied for和He failed to come that evening。在作“不成功”解的时候可以把那不定式改作in和动名词。例如：He failed in obtaining the information he had applied for. 在作“不…”解的时候不可把那不定式改作in和动名词，如不可说He failed in coming that evening。
3.He failed in the examination和He failed in Latin都是正常的英语。下面各句里的failed用作及物动词，是美国学校里的用法：
- He failed the examination.
- He failed Latin.
- The professor failed him in Latin。
4.failed用作形容词作“已失败的”解在美国比在英国普通，如a failed author和a failed firm。
5.下面两句语法不同，意思也往往不同：
- His arrival failing, I shall write again. His arrival failing是独立结构，通常作“因为他不到”解，但也可作“假使他不到”解。
- Failing his arrival, I shall write again. Failing从现在分词转用作介词，Failing his arrival通常作“假使他不到”解，但也可以作“因为他不到”解。
