For barrier synchronization add a B, for fence synchronization add an F, and for no synchronization you do not need to add anything.

对于 barrier 同步会增加一个 B，对于 fence 同步会增加一个 F，对于无同步则不会增加任何内容。

youdao

The fence would extend 1,120 kilometers along the entire U.S.-Mexican border, but not all of it would be an actual barrier.

围墙将沿着整个美国—墨西哥边境延伸1120公里，但并不是所有的都是实际屏障。

youdao

Because transfer 2 only USES a fence and transfer 3 doesn't specify any ordering at all, transfer 3 is free to float anywhere before the barrier (transfer 4).

由于传输2只使用了一个fence，而传输3根本就没有指定任何次序，因此传输3可以在barrier(传输4)之前的任何地方执行。

youdao

There is no fence. They come across this barrier, right up here.

VOA: standard.2010.06.07

Just before I reached the barrier fence, I found Mu Zhenxian, sitting at a low table behind her earthquake wares.

NPR: Ruined Beichuan Starts Anew

One of the byelaws prohibits "people climbing on any wall, fence, tree, barrier, railing or structure without a reasonable excuse".

BBC: New laws to combat 'tombstoning' in East Yorkshire

Rancher Carol Kimsey, who lives in a valley near the Pacific Ocean on the U.S.-side of the fence, says the border barrier has improved the quality of life in the area.

NPR: San Diego Fence Provides Lessons in Border Control