1.   Whether       he can do it is a problem.

2.It makes no difference to me     whether       you like it or not.

3.   Whoever       does wrong to his country or to the people deserves punishment.

4.   Which       charity they will go to has not been decided.

5.   Why       he turned down the invitation was not clear.

6.   That       the earth goes around the sun is known to us all.

7.   What       side effect this medicine has is not known to the patient.

8.It is still unknown        whether       the medicine will be effective.

9.It is not clear     how       he got here without any money.

10.   What       she couldn’t understand was that fewer and fewer students showed interest in science.