out of ... ^{出于...（原因状语）}

• I’m turning to you out of desperation.
• Let us never negotiate out of fear, but let us never fear to negotiate.
• The children hid under the bed out of fear when the thunder started. ^{雷声响起时，孩子们出于恐惧躲到了床底下。}

sport ^{乐趣、好玩、消遣}

• Modern alpinists try to climb mountains by a route which will give them good sport...
• They were only doing it for fun.
• Oh, you're being a really good sport about this... ^{表现得非常有风度}

as in doing sth. ^{如同做某事（省略主语成分的状语从句）}

On the occasions when they have pushed to shore an unconscious human being they have much more likely done it out of curiosity or for sport, as (they have done it out of curiosity or for sport) in riding the bow waves of a ship. ^课文补全

• Air is to man as water is to fish. ^{(书面语中)表示“像…一样”一定是连词}
• In New York, like ^X as in some other cities, environmental pollution is becoming more and more serious. ^{老托福语法改错题}
• In New York, as environmental pollution is becoming more and more serious ^(补全) in some other cities, environmental pollution is becoming more and more serious.
• It is almost always due to some very special circumstances that traces of land animals survive, as by falling into inaccessible caves, or into an ice crevasse, like the Siberian mammoths, when the whole animal is sometimes preserved, as in a refrigerator.
• It is almost always due to some very special circumstances that traces of land animals survive, as traces of land animals survive^(补全)  by falling into inaccessible caves, or into an ice crevasse, like the Siberian mammoths, when the whole animal is sometimes preserved, as the whole animal is preserved^(补全) in a refrigerator.

In 1928 some porpoises were photographed working like beavers to push ashore a waterlogged mattress.

photograph sb. doing sth. ^{拍下某人正在做某事}

• They were photographed playing with the children.
• The journalist managed to photograph the celebrity leaving the secret meeting. ^{这位记者设法拍下了这位名人在秘密会议后离开的照片。}

beaver ^海狸

• The conservation group is monitoring the local population of the Eurasian beaver. ^{这个保护组织正在监测当地欧亚海狸的数量。}
• The construction crew worked like beavers to finish the project on time.

If, as has been reported, they have protected humans from sharks, it may have been because curiosity attracted them and because the scent of a possible meal attracted the sharks.

as 引导非限定定语从句 (区别于 which)

1. as 作为关系代词指代整个主句，而 which 作为关系代词指代整个主句或先行词均可。
2. as 引导的非限定性定语从句位于主句前、中、后均可，而which 引导的非限定性定语从句不能位于主句之前。
3. as 引导的非限定性定语从句含有“众所周知”的意思，常译为“正如……”，而which 引导的非限定性定语从句则未必有这个意思。
4. 在“as + is/was + done”结构中可省略“is/was”，而在 “which + is/was + done”可省略“which + is/was”，而不能只省略 be 动词。

• As a poet points out, life is but a dream. 
• Children, as is always the case, love their mother.
• She became angry, as many could see.
• As is so often pointed out, knowledge is a two-edged weapon... 
• As is so often pointed out, knowledge is a two-edged weapon which can be used equally for good or evil.
• The sun heats the earth, which makes it possible for plants to grow.^{（不能换成as，没有“正如”的含义）}
• As (is) reported, a foreign delegation will visit the city. 
• a puma (which was) at large 

If, as reported, they have protected humans from sharks, … ^课文简写

• As Napoleon once pointed it ^X out, attack is the best method of defense.  ^{多了宾语（美式）}
• Cave exploration, or pot-holing, as it has come to be known, is a relatively new sport. ^{美式英语会认为是错的（as引导非限定性定语从句），英式认为as引导方式状语从句}
• The problem, as I see it, is no big deal. ^{错与对是根据英式还是美式}
• The author was brought up in a small village, as it is recounted in some of his stories. ^{雅思这句没有问题，托福就属于错误}

it may have been because ... ^{原因可能是因为...}

• It is because of your help that I succeeded. ^{正是因为你的帮助我才成功了.}
• The reason I left is that I was unhappy. ^{我离开的原因是我不开心.} 
• The reason is because I was unhappy. ❌

… it may have been because curiosity attracted them … ⇒ … the reason may have been that curiosity attracted them … ^{课文写法替换}

Porpoises and sharks are natural enemies.

natural enemies ^{天敌(复数名词表类别)}

• The fox is the natural enemy of the rabbit.
• This rabbit had no natural enemies in the Antipodes, …
• Birds are natural enemies of insect pests of human bird friend. ^{鸟是害虫的天敌鸟是人类的朋友。}

It is possible that upon such an occasion a battle ensued, with the sharks being driven away or killed.

it is possible that ... ^有可能...

• It is possible that there is a definite relation between these paintings and the markings that sometimes accompany them.
• It is possible that he missed the train.
• Yes, it is possible that we forgot to buy cinnamon. ^{是的,我们可能忘了买桂皮粉。}