keep sth at bay : 远离xx
e.g.they help to keep parasites at bay.
烟头 ：cigarette butts
干涉、搞乱 ：meddle with the nests
一旦xx到位 ： once... were at place,
e.g. Once the new linings were in place, the researchers added parasites to some of them.
吸血的寄生虫 ：bloodsucking parasites
衍生 ：吸血的吸血鬼：bloodsucking vampire
e.g. showed that nests which had butts woven into them were less likely to contain bloodsucking parasites than were nests that did not.
分析 ：had done 结构+比较级
e.g. What she was unable to show was whether the nest-builders were collecting discarded cigarettes deliberately for their parasite-repelling properties, or whether that parasite protection was an accidental consequence of butts being a reasonably abundant building material.
分析 ：what 从句+whether*2,
同义词替换 ：nest-builder 替换birds, 因为build nest 与主题相关；
e.g.To discover the truth, Dr A and Dr B set up an experiment involving house finches that were nesting on their campus.
分析：可用句式多样性，to 表目的开头，主谓宾+v-ing+that
twigs : small branch, 嫩枝
eclectic: selecting what seems best of various styles or ideas 兼收并蓄的
在文中指选择建鸟巢的材料更加多样性，可联系elastic 来记忆；
aluminium foil : 铝箔
make do: manage with what's available
e.g. Most of these have been assumed to be the result of birds simply making do with what the urban world provides them, but a study just published in Avian Biology by Monserrat Suárez-Rodríguez and Constantino Macías Garcia of the National Autonomous University of Mexico has demonstrated that the cigarette butts are being woven into nests not by accident but by design.
注意，but 前是逗号，
finches : 雀科
linings : 衬里，内层，这里指鸟巢垫底部分的材料
wreathed ：缠绕
ticks : 这里指一种parasites, 壁虱
fledge ：羽翼丰满、长羽毛
felt : n. 毛毡
fumigate : 烟熏，联想词根fume 烟来记忆
原文链接： https://www.economist.com/news/science-and-technology/21729739-they-help-keep-parasites-bay-some-birds-use-discarded-cigarettes-fumigate
SST: A study demonstrated that cigarette butts are being woven into nests not by accident but by design, which has not been proved since 2012,
until scientists conducted an experiment by putting living ticks and dead ticks as a control group to see the results, which proves that cigarette butts are woven by birds to keep parasites at bay. (呼应but by accident)
SWT总结: 同上