★immensity n. 巨大
located... 是过去分词短语作定语，修饰 situation;
in the midst of which 引导一个定语从句，which指two small hills。句子结构要倒装（flowed 在a great river之前）
in the midst of, 在......之中。
in the midst of two small hills flowed a great river
A great river flowed in the middle of the two hills.
in the middle of the night == at midnight
in the middle of the winter
★capacity n. 承受量
Are you clear about the capacity of the cinema?
have a capacity for doing sth.
have a capacity to do
We have ability to finish the work in two days.
have capability to do
have capability of doing
Any chile has capability of learning a foreign launguge well.
Any chile has capability to learn a foreign launguge well.
the faculty of seeing
the faculty of hearing
I have competence for the job.
★elegant adj. 优美别致的
The lady is elegant.
★faintly adv. 微细地
sailed into.. ----句子的主干
describe sth. as 把......描绘成......，认为 ......
常见的动词有：see, view, look upon, recoginze, regard, treat, accept
Eg.: I should describe the attempt as a failure.
His mother regards him as genius.
I accept his words as true.
located within two small hills in the midst of which floweda great river
hold up 支撑
a railway extends to the next city
extend to a depth of 深度
extend to a length of 长度
extend to a width of 宽度
rise to 上升的高度