1. He didn't come because of his sickness.

-> ......because he was sicj, he didn't come........................................................

2. The train was late because the fog was trick.

-> ........because of the trick fog, the train was late..............................................................

3. The plane couldn't take off because ò the bad weather,

-> ....because the weather was bad, the plane couldn't take off...................................................................................

4. He left the school because hí family was poor.

-> ........because of his poor family, he left school................................................................

5. We couldn't study because of the noise.

-> ..........because it was noisy, we couldn't study.....................................................