練習(xí)材料：
[Day 1751 2019-07-13]
Lesson 20-2 Snake poison
In fact, it would be an assistance to all carnivores though it would be a two-edged
weapon when they fought each other. But, of the vertebrates, unpredictable Nature
selected only snakes (and one lizard). One wonders also why Nature, with some snakes,
concocted poison of such extreme potency.
In the conversion of saliva into poison, one might suppose that a fixed process took
place. It did not; some snakes manufacture a poison different in every respect from that
of others, as different as arsenic is from strychnine, and having different effects. One
poison acts on the nerves, the other on the blood.
The makers of the nerve poison include the mambas and the cobras and their
venom is called neurotoxic.
任務(wù)配置：L0+L1+L4
知識筆記：
carnivores? ? n. 食肉動物;
vertebrates? ? n. 脊椎動物(包括所有哺乳動物施逾、鳥類、魚類炉爆、爬行動物和兩棲動物);
concocted? ? v. 調(diào)制柑晒，調(diào)合总处，配制(尤指食物或飲料); 虛構(gòu)漓帅，杜撰埠况，編造(故事、借口等);
potency? n. 影響力; 支配力; 效力; (男子) 性能力昭殉，性機(jī)能;
arsenic? ? n. 砷;
strychnine? ? n. 士的寧; 馬錢子堿;
mambas? ? n. 樹眼鏡蛇(黑色或綠色苞七，分布于非洲，有劇毒);
cobras? ? n. 眼鏡蛇(毒蛇挪丢，分布于亞洲和非洲);
venom? ? n. (毒蛇蹂风、蜘蛛等分泌的) 毒液; 惡毒; 怨恨; 惡意; 歹心;
neurotoxic? ? adj. 神經(jīng)毒的；毒害神經(jīng)的;
練習(xí)感悟：
