Billy: I’ve been fixing the computer for over three hours, but it still doesn’t work. Nana: Why don’t you take a rest and try ? Maybe you’ll do better then.

________ has already been pointed out, only by correcting mistakes can you make progress.

Did you find __________very interesting to play yo-yo?

______ do you go to bed in the evening? [ ]

Which is the smallest number of the four?–________.