If it is observed that there is no obvious phenomenon in the glass conduit and there is a blue flame phenomenon at the conduit mouth, then Beibei's guess is correct;
If Fangfang's guess is correct, the paraffin vapor generated by candle heating will cool after entering the catheter and can condense into paraffin, so there is solidified paraffin in the glass catheter, and there is no obvious phenomenon at the opening of the catheter, which proves Fangfang's guess is correct;
If the above two phenomena exist, that is, there is solidified paraffin in the glass conduit and blue flame at the conduit mouth, then Tingting's guess is correct.
Experimental scheme
(1) Carbon dioxide will make clear limewater turbid. When blowing out the candle, immediately cover the white smoke with a beaker with clear lime water to verify hypothesis A; However, due to the residual carbon dioxide produced by burning around the candle that has just been blown out, it is impossible to draw a correct conclusion;
(2) Blow out the candle and immediately put a piece of dry and cold glass on the white smoke. There is no water mist on the glass sheet, indicating that smoke is not water vapor;
So the answer is: water vapor;
(3) Blow out the candle, immediately remove the white smoke from the burning wood (don't touch the wick), and find that the candle is rekindled, which proves that the smoke is combustible, which proves the correctness of hypothesis C; Because neither steam nor carbon dioxide can burn, this also proves that AB's hypothesis is incorrect.