So it’s been known for some time that birds which eat fish may be affected, but what wasn’t known until quite recently is that those that eat insects can also be affected.
详细的解题思路：这个题的考查其实很简单，eat insects就是 feed on insects，所以答案是insects。
And these may be to do with the behaviour of the birds, or with the effect of mercury on the wav their brain works, so whether it leads to problems with memory, for example.
详细的解题思路：be to do with the behaviour of the birds，也就是和鸟类的行为有关，所以答案是behaviour。
Now, the process of song learning happens at a particular stage in the birds’ development, and what you may not know is that a young bird seems to acquire this skill by listening to the songs produced by its father, rather than by any other bird.
详细的解题思路：learn from 也就是和原文的acquire by…by…是同义表达，所以答案是father。
And Varian-Ramos has already found in her research that if young male birds are exposed to mercury, if they eat food contaminated with mercury, then the songs they produce aren’t as complex as those produced by other birds.
详细的解题思路：are not as adj. as… 这个结构就是less adj. than，所以答案是complex。
So quite low-level exposure to mercury is likely to have an impact on male birds in a natural situation, because it can mean that they’re less attractive to female birds, and so it can affect their chances of reproduction.
详细的解题思路：affect和have a effect on…属于同义表达，所以答案是reproduction，同义词还有breeding，所以答案是reproduction/breeding。
The lab-based studies have the advantage that you don’t get all the variables you would in a natural setting, so the experimenter has a much higher level of control, and that means they can be more confident about their results in some ways.
详细的解题思路：研究者做了两种实验研究，一种在实验室的室内研究，一种是室外的野外的研究，然后比较了一下，基于实验室的室内研究的优势就是对实验者而言，可控制可管理的因素比较多，a much higher level也就是more的同义表达，所以答案是control。
So what are the implications here for humans? Well, because many birds are migratory, they may be transporting mercury far from contaminated sites. For example, it’s been found that ducks who’d been feeding at a contaminated site were later shot by hunters over a thousand kilometres away. and presumably eaten.
详细的解题思路：Q37-40是考查“Implications for humans”这个部分的内容，这个部分在原文重现，所以后面就是我们需要特别注意听的答案。For example和题干的such as 属于同义表达，所以答案是ducks。
Well, we also know that in humans, mercury causes developmental delays in the acquisition of language, and in fact this process is very similar in the brain regions it involves and even the genes that are involved.
It’s now known that an unborn child can be affected if the food eaten by its mother contains high levels of mercury, and these effects can be quite substantial.
详细的解题思路：can be affected 和题干的主动语态affect也是同义表达，只不过调换了主语的位置，而且 food eaten by its mother，就是from mother’s food，所以答案是food。
It’s true there are new regulations for mercury emissions from power plants, but these will need billions of dollars to implement, and increase costs for everyone.
详细的解题思路：来自发电厂的汞排放有新的规定，但是需要大量的钱投入，又是but后出现重要信息，最重要的affect 就是increase cost for everyone，所以答案是cost(s)，也可以是同义表达的cost(s)/price(s)/bill(s)。