1.signature n.签名，签字(person's name written by himself)
词根记忆：sign(记号)+ature--加自己名字做记号--签名
例：A check's authenticity includes reminders to watch the endorsement, compare signatures, and view the watermark while holding the check to the light.
同根词：signify(v.表示：意味)
2.significance n．意义：重要性(the quality of being important)
词根记忆：来自significant(a．有意义的；重大的)
例：A phenomenon is described and its scientific significance is dis- cussed.
同根词：signify(v.表示；有重要性)
3.significant a．相当数量的(considerable)；意义重大的{having an important meaning）
词根记忆：sign(记号)+i+fic(做)+ant--值得做记号的--意义重大的
例：Their removal may not have led to significant increases in populations of smaller predators.
派生词：significance(n．意义)；significantly( ad.显著地)
同根词：signature(n．署名，签名)
4.signify v.表示，意味着(to mean)
词根记忆：sign(信号)+ify--用信号表示
例：Dark clouds signify that it will rain soon.
5.silkworm n．蚕，桑蚕(a moth whose larva spins a large amount of strong silk in constructing its cocoon)
分拆记忆：silk(蚕丝)+worm(虫)--吐蚕丝的虫--蚕
例：The gypsy moth was imported into Massachusetts from Europe in 1869 by a French scientist attempting to develop a strong strain Of silk- producing insects by crossing gypsy moths with adult silkworms.
6.similarity n．相似点(the quality or state of being similar)
词根记忆：来自similar(a．相似的)
例：Almost like clones in their similarity to one another, members of the cheetah species are especially vulnerable to disease because of their homogeneity.
同根词：dissimilar(a．不同的)