1.There has long been a superstition among mariners that porpoises will save drowning men by pushing them to the surface, or protect them from sharks by surrounding them in defensive formation.
There has long been，也就是说there has been…since long long ago。superstition是迷信的意思。
例如：Superstition is still running rife in the country in China.
在中国乡村迷信仍很盛行。
protect from 保护……免于……
The greenhouse protects vegetable from cold.
温室保护蔬菜免受冻害。
2.Marine Studio biologists have pointed out that, however intelligent they may be, it is probably a mistake to credit dolphins with any motive of lifesaving.
point out 指出，指明
I pointed out the problems of the government.
我指出政府的问题。
however在这里相当于no matter how。不过两者之间存在差别。
However和no matter how同义，都表示“无论如何”的意思，又都引导让步状语从句，但它们的修辞意味和使用场合有所不同。
However是比较正式的用语，大都用于书面语，口语中较少使用；no matter how则比较口语化，它的语势比however重，故常用在强调的场合。
请看下面的例句：
The task must be done，however arduous it may be．
无论多么艰难，这个任务一定要完成。
（试比较一般句：The task must be done though it is arduous．）
I'll take your words，no matter how harsh they may be．
无论语气多么难听，我还是听你的话的。
（试比较一般句：Although your words are harsh，I'll take them．）
However有时可表达“然而”、“可是”之意，出现于句中或句尾。例：
They said that it was so；they were mistaken，however．
他们说事情就是如此，可是他们错了。
与之类似区别的词语很多，例如：whatever/no matter what、whenever/no matter when、wherever/no matter where、whichever/no matter which、whoever/no matter who。
