flat 平坦的 波澜不惊的，缺乏热情的，无光泽的，色彩单调的等等
其反义词有曲折的winding，flexural，meandering等，热情的enthusiastic，passionate，zealous等 ，有光泽的glossy，lustrous等等
①曲折的meandering
Back in the dinosaur era， it was more of a floodplain environment， with a flat plain crisscrossed by big， meandering rivers.
在恐龙时期这个地区则更多为泛滥平原环境，平坦的平原上纵横交错着大而曲折的河流。
②热情的passionate
You can recognise a person who is passionate about a pursuit by the way they are so strongly involved in it.
你可以通过一个人对一件事的投入程度来判断他对这件事的热情程度。
③有光泽的glossy
Her hair was thick， glossy and in tiptop condition.
她头发浓密、有光泽且发质一流。
