Boats travel back and forth on the canal.

运河上的船只来来往往。

The notion that we can travel back in time is preposterous.

认为我们可以回到过去的想法是荒谬的。

This railway is a double track, so trains can travel back and forth simultaneously.

这条铁路是双轨的，所以火车可以同时来回行驶。

To find answers, we must travel back in time.

要找出答案，我们必须回到过去。

Travel back 70 million years to the prehistoric world.

回到七千万年前的史前世界。

I want you to travel back in time with me, to the before time, to 2017.

我想让你们和我一起回到过去，一起回到2017年。

The resulting coral larvae travel back down to make their home on the reef.

繁殖的珊瑚幼虫会返回海底在珊瑚礁上安家。

If we travel back in time 20,000 years ago, the earth looked very much different.

如果我们让时光倒流两万年，整个地球看上去非常不同。

Under the premise of the invariable rotation, enables the automobile to travel back;

②在发动机旋转方向不变的前提下，使汽车能倒退行驶；

But if you were to a time travel back when they were around, I don't recommend you poking them.

但如果你回到他们生活的时代，我建议你不要逗他们。