A.
Practically every river has an upper, a middle, and a lower part. 【译文】但凡是河流,都有上游、中游和下游。
B.
The purposes of his journey were both military and political. 【译文】这次旅行既有军事上的目的,又有政治上的目的。
C.
Know the true value of time; snatch, seize, and enjoy every moment of it. 【译文】知道时间的真正价值。才能争取每一刻,抓住每一刻,享受每一刻。
D.
It must be morning now, because the birds are singing. 【译文】一定是天亮了,因为鸟儿在歌唱。