1) We drove very slowly because the roads were icy.
=> Because of the icy roads, we drove very slowly
=> The roads were so icy that we drove very slowly
2) They didn't buy the house because of its high price.
=> Because the price was high, they didn't buy the house
=> The price was so high that they didn't buy the house
3) Because of the cold weather, she wore a coat.
=> because the weather was cold, she wore a coat
=> The weather was so cold that she wore a coat
4) She left sleepy because of the long performance.
=> Because the performance was long, she left sleepy
=> The performance was so long that she left sleepy
5) Because it rained heavily, they stayed at home.
=> because of the heavy rain, they stayed at home
=> It rained heavily, so they stayed at home