The air would be hard to breathe, why not be passive

This one is a bit of a special structure, and you can remember it like this, to breathe the air would be hard, if you put it behind.

The infinitive and the subject form the infinitive + object to be the subject, and the meaning is unchanged from the original sentence.

Even if you don't use the passive voice, that's what I remember.

For example: mary is not easy to work with and to work with mary is not easy

Without adding that, it means that the sentence after it is and the main clause.

Because the sentence after and the clause before and before are both objects that do told, that leads the object clause and can be omitted.

There is no need to add can be omitted.

When I told her that air is hard to breathe.

Translation Result: When I told her about the air that was hard to breathe.

When I told her the air here wasn't good for breathing.

When I told her that the air was thin and it was hard to breathe.

When I told her, I was so depressed that I couldn't breathe!

I like my sister, but she has a serious drawback. She's going to be stubborn. Even though she didn't know the best way to get there, she insisted on making the best arrangements for the trip herself.

Now I know that the right path is always her path. I kept asking her, "When we're leaving, when we're coming back?" I asked her if she was looking at the map.

Of course, she didn't; My sister doesn't care about details. So I told her that the source of the Mekong River was in Qinghai. She gave me a determined look – a look that showed she wasn't going to change her mind.

When I told her that our journey would begin at an altitude of more than 5,000 meters, she seemed excited about it. When I told her it was hard to breathe air and that it would be cold, she said it would be a fun experience. I know my sister.

She had made a decision that no one could change it. In the end, I had to give in.