This is a long river.

这条河很长。

《新英汉大辞典》

As well as the flowers, people would also meet various ill of life, but the long river of people's life is without end.

花和人都会遇到各种各样的不幸，但是生命的长河是无止境的。

youdao

Even 100 year old, it may be prolonged in a person's life, but comparing with the long river of history it is quite short.

就算100岁吧，在人的一生中可能是漫长的，但在历史的长河中也是相当短暂的。

youdao

Then he got up, found a long stick and walked up and down the river bank.

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