1. impossibility => impossible 

2. all=>no one

3. in=>of

4. understood=>understanding

5. friend=> friends

6. on=>for

7. look over=>to look over

8. about=> with

9. close=>closely

10. least=>less

1. When mutual sympathy does not exist, friendship is impossibility.(impossible)

2. Everyone has a number of acquaintances, but all has many true friends.(no one)

3. Some people are incapable in finding good friends.(of)

4. It is comfortable to work with such an understood person like him.(understanding)

5. I made friend with Lan when she was on her trip to Do Son.( friends)

6. Soon after Jonh has finished thesis, he will leave for Boston, where he has a job waiting on him.(for)

7. The Nelson asked us look over their plants for them while they were away on vacation.(to look over)

8. Paris has been well-known about its splendid monuments, beautiful music and wonderful restaurant for over one hundred years.(with)

9. Peanuts are close related to peas than to nuts.(closely)

10. Most evergreens have needle-like leaves that require least water than regular leaves.(less)