I made up several sentences. Could you please check them?

1. He took a long deep breath looking at that unbelievable castle surrounded by old trees as if someone long since had put a spell on it.

2. You know, you look sluggish today. If you feel unwell, <s style="background-color: rgb(255, 255, 102);">I can give you a spell (rest?) for several hours </s>you can rest for a few hours.

3. For a moment I <s style="background-color: rgb(255, 255, 102);">slacked</s> slowed down my pace greeting my friend on the other side of the street.

-These last sentences have already been checked but I have a doubt that everything is correct. Please, fix it one more time:

4. Bright sun, snow, a light melody heard from afar. Straightening, Kate stepped forward and slid<s style="background-color: rgb(255, 255, 102);">e</s> over the sparkling ice. Now she herself looked like a snowflake swirling in the frosty air.