8 auroral adj. 北極光的；
9 bicameral a. 兩院制的,有兩個議院的；
10 bilateral a. 有兩面的,雙邊的,雙方的。
例句：
I strongly disagree with this amoral approach to politics.
我強烈不同意這種對政治采取非道德化的態度。
Early embryos of many species develop ancestral features.
許多物種的早期胚胎具有其祖先的'特性。
This ancestral species might have evolved at a time when the islands were connected.
這種祖先物種可能是在島嶼相連的時候進化而來的。
Of today's different groups of algae, green algae are probably the most similar to ancestral plants.
在今天的眾多藻類中，綠藻可能與植物的祖先最為相似。