I just go by what I see on the river as I walk it down.只通过漫步河畔途中所见来判断。

go by:经过, 走过

He was watching the crowd go by.

他注视着人群走过。

Saturday afternoons go by like lightning!

星期六的下午象闪电一样转瞬即逝！

I back and forth every day on the river我每天都在河畔来回漫步

back and forth:来回地, 反复地

He rocked back and forth in his rocking chair.

他坐在摇椅里前后摇晃着。

He fluttered back and forth in the corridor.

他在走廊上烦躁不安地走来走去。

but in the meantime,the people of Hay River have a remarkable guardian.但同时草河的居民拥有优秀的守护者

in the meantime:与此同时, 在此期间

In the meantime, he gave me a lot of good advice.

同时他给我提了很多好的建议。