区别：

all but 几乎，差一点，除……以外其余都是

but for要不是

but that+从句：若不是……

例1：She all but fainted when she heard the news.

译文：她听到这一消息时几乎晕倒了。

注：此句中a11 but意为nearly，almost。

试对比：

All but the little children thought that the trip was exciting.

译文：除了小孩，大家都认为这次旅行是激动人心的。

此句中all but意为a11 except。

例2：But for the rain we should have a pleasant journey.

译文：要不是下雨，我们的旅行本来是愉快的。

例3：He would have helped us but that he was short of money at the time.

译文：若不是他那时缺钱，他是会帮助我们的。

注1).but that引导的从句中谓语用陈述语气。2).but that有灵活的译法。如：Nothing would satisfy that child but that I place her on my lap.(那孩子什么都不要，只要我把她抱在怀里。)

3.“名词+or+名词”结构中or后的名词是同位语，应译为“即……；或者称……”

例1：Moreover, technology includes techniques, or ways to do things, as well as the machines that may or may not be necessary to apply them.

译文：再者，除机器外技术还包括技艺，即制作方法，而动用这些技艺并不一定都需要机器。

4.“only + to do”意为“……，结果却……”，即表示与句子谓语动作的目的相反的结果。

例1: They don"t have to pay for expensive seats at the theatre, the cinema or the opera, only

to discover, perhaps, that the show is disappointing.

译文：他们不必花钱去戏院、电影院或歌剧院买价格很贵的票，(如果去了，)结果却可能发现，所演的节目令人失望。

例2: They hurried there only to find the meeting canceled.

译文：他们匆匆忙忙赶到那儿，结果却发现会议被取消了。

5.not more / -er than 与 no more / -er than 结构

比较：

John is not better than Tom.

John is no better than Tom.

前一句表示“约翰不比汤姆好”，属于普通的比较结构；后一例用了no 情况就不同了。no better than 相当于as bad as，含义是两人一样坏。这里，“no + 形容词或副词比较级 + than”所表示的可以说是该形容词或副词的反意。

例如： no richer than = as poor as 和……一样穷

no bigger than = as small as 和……一样小

no later than = as early as 和……一样早

同样地：

I have not taken more than six courses this semester.

I have taken no more than six courses this semester.

前一句的含义是本学期选的课不多于六门；后一句的含义是只选了六门。强调“少”。

上述结构与表示前后都否定的no more...than (= not...any more than)又有所不同：

例：A whale is no more a fish than a horse is.(鲸和马同样不是鱼。)

另外，在某些结构中，单独使用more than 也能表示否定概念：

例1：That is more than I can tell. 我简直不能说。

例2：My trip to Beijing is more than sightseeing. 我去北京不仅仅是旅游观光而已。

6.no more...than... (= not...any more than) 和……—样都不……(表示前后都否定)

例1：The heart is no more intelligent than the stomach, for they are both controlled by the brain. 心脏和胃一样都无智力可言，因为它们都是由大脑控制的。

例2：There is no reason they should limit how much vitamin you take, any more than they can limit how much water you drink.

译文：他们没有理由限制你服用多少维他命，就像他们不能限制你喝多少水一样。