He doesn't know his friend's new address
 - He wishes he knew his friend's address
2. Alexander Graham Bell invented the telephone in 1876
 -  The telephone was invented by Alexander in 1876
3. Why don't you turn off the lights before leaving your classroom?
 - I suggest you turning off the lights before leaving your classroom
4. They had to cancel the light because the weather was bad
- The weather was bad, so they had to cancel the light