Помогите пожалуйста перевести предложения на английский.

Самый лучший перевод, конечно, у Alice, но в двух последних предложениях я бы сказала иначе.
When I entered the room, I saw Ann, where I had left her.- полностью согласна с Alice in Wonderland
We had been driving for two hours, when we finally saw the lake. - полностью согласна с Alice in Wonderland
When he came home, he knew, that his sister had just left. - know = "знать". Получается, что Приехав домой, он Знал, что его сестра только что ушла.
Чтобы получить "Узнать" берём либо глагол learn, либо фразу get to know и ставив в Past Sipmle Tense - When he came home, he got to know, that his sister had just left.
I was surprised by the progress she had made, taking into consideration, how little time had passed since I saw her last. - после since я бы употребила Past Simple, а не Past Perfect, хотя, конечно, видел он её ДО того, как ему пришлось удивляться, то есть так называемое "предпрошедшее" действие, с одной стороны, очевидно, но слово last и предлог since всё-таки заставляют меня предпочесть форму Past Simple.

When I entered the room, I saw Ann, where I had left her.
We had been driving for two hours, when we finally saw the lake.
When he came home, he knew, that his sister had just left.
I was surprised by the progress she had made, taking into consideration, how little time had passed since I had seen her last time.

П. С. Не пойму, почему предыдущие участники "ее" переводят как "it"....

Ого.. . чёт и у меня заржавело!

Coming into the room, he saw Anne where he had left her

We had been travelling for about two hours straight, when we saw that lake at last.

On coming home he learned his sister had just gone.

I was amazed at (/by) her progress, considering the fact that little time had passed since I had seen her last

Entering the room, he saw Anne, where it had left.

We drove about two hours when I finally saw the lake.

Arriving home, he learned that his sister had just left.

I was surprised at what progress it has made, given how little time has passed since I saw her last time.

Entering the room, he saw Anne, where it had left.

We drove about two hours when I finally saw the lake.

Arriving home, he learned that his sister had just left.

I was surprised at what progress it has made, given how little time has passed since I saw her last time.