词根：-sit-(变形: sid, sad, sed) 1. 坐; 2. 旁边
实例：Hand tools are relics of the past that have now been superseded by the machine.
实例：dissident shareholders, dissident party
(11) insidious 潜在的, 阴险的
实例：The insidious effect of the operational change cannot be neglected.
近义词: assiduous, diligent
实例：She is as gifted as sedulous.
(13) residue残余, 残渣; 残余物
实例：Always using the same shampoo means that a residue can build up on the hair.
记忆方法：sed(坐)+ ent+ ary(形容词后缀)→ 坐着的
实例：Obesity and a sedentary lifestyle has been linked with an increased risk of heart disease.
(1) assort 分类,和…合拍(匹配),和…是一类
实例：He cannot assort with people in his own age.
(2) consort 和…一类(鬼混), 配偶
衍生: consortium 联盟,财团
实例：He regularly consorted with known drug-dealers.
实例：“It’s also first steps, over time, toward governments trusting Airbnb to assume more responsibility for regulating their hosts.”(New York Times, May 1, 2017)
实例：He hopes to clear his name and resume his career.
(3) presume 假定
注意：Assume and presume both mean to believe something before it happens, but when you assume you're not really sure. If someone bangs on your door in the middle of the night, you might assume it's your crazy neighbor. If your neighbor knocks on your door every night at 6:30, at 6:29 you can presume she's coming over in a minute.
实例：If you are presumed to be the fastest runner, don't get too cocky — that word implies that you haven't actually raced yet.
实例：She produces elegant wedding gowns in a variety of sumptuous fabrics.
实例：He has developed a consuming passion for chess.
记忆方法：un(不,无,非,没有)+ as(加强动作)+sum(=sume 拿,取)+ing(现在分词表形容词)→ 不拿架子的→ 谦逊的, 低调的
近义词: genuine, meek, sincere, modest, unpretentious, humble
实例：He's a man of few words, very polite and unassuming.
(1) assure 保证
实例：I assure you it’s temporary. I assure you it’s transitory. The American people will not sustain this attitude,” he said. (The Guardian, May 21, 2017)
(2) ensure 保证
注意：assure / ensure / insure
Although these three often show up at the same party, giving hugs, they’re not the same, thank you very much. To assure is to tell someone everything’s ok, to ensure is to make certain, and to insure is to protect financially. Have it straight now? Are you sure?
实例：The first minister will say Wales needs two Labour governments to ensure the economy works "for everyone". (BBC, May 21, 2017)
词根：-ton-(变形: ton, tound, tun) 声调→高声调"当~~"→吃惊
(1) astonish 使吃惊
实例：Things that might astonish you: the discovery of life on another planet, a death-defying performance, and the number of dinosaurs a six-year old child can name.
实例：To astonish is to amaze and astound.
衍生: stunning 极好的, 类似于awesome
实例：Many cinema-goers were stunned by the film's violent and tragic end.
(20) dilettante (贬义)
实例：He is a master of that area even if he is a dilettante.
实例：The test assessed his manual dexterity, math skills, and sociability, and concluded that he should become a database developer, a podiatrist, or a nurse. (New Yorker, May 19, 2017)
实例：To ameliorate is to step in and make a bad situation better.
实例：The book was released earlier this month and features some 250 posts from the site, including emotional personal anecdotes.
实例：Women who worked with him paid it in humiliation and psychological anguish.
(25) languid 懒散的,无精打采的
实例：Time spent at Jumby Bay can be as energetic or as languid as you wish.
(26) sanguine 有血色的,乐观的
实例：If you're sanguine about a situation, that means you're optimistic that everything's going to work out fine.
(27) plummet铅锤, 突然落下
实例：In 2016, fuel prices on the open market plummeted even more, enabling the Pentagon to build an even bigger surplus in the working-capital fund. (Washington Post, May 20, 2017)
(28) prudence拘谨 (更多是性方面的)
衍生: prudery , prudish
近义词: cautiousness, rigor 反义词:imprudence, 参见impertinence
实例：White House officials may once again understand that gravity, prudence, probity and diplomacy are valuable and essential qualities in a president.(The Guardian, May 20, 2017)
实例：Arboreal animals live in trees.
(30) aristocrat 贵族
记忆方法：记忆: aris=arise + to→arise to 贵族
实例：An aristocrat is someone from the ruling class, usually those with nobility, money, or both.