4. The machine-readable medium of claim 3 wherein said display mode requires the other of said subject matter and said query or instruction that is presented in (ii) to replace the one of said subject matter and said query or instruction that is presented in (i).
4. The machine-readable medium of claim 3 wherein said display mode requires the other of said subject matter and said query or instruction that is presented in (ii) to replace the one of said subject matter and said query or instruction that is presented in (i). 6. The machine-readable medium of claim 4 wherein said instructions further cause said computing device to repeat (i) after (ii) upon user request and to store a measured duration of the repeated (i).