1. It's not necessary for you to do the test
-> You...............................................
2. Nobody can deny that she has a beautiful voice
-> It........................................................
3. The could not trace who had supplied the information in the first place
->The course...................................................
4. I gave Tom the message, but he already knew about it
-> I needn't.......................................................
5. It is esseential that no one be told about our plans
-> You......................................
6. It was wrong of you not to call the doctor at once
-> You.............................................................