Converting system of 3 phase power to single phase power

How do you convert a 3 phase power to single phase power?
[Ashuganj Power Station Company Limited- 2011]

Ans: For three phase , three wire system, the load between any two of the three line conductors (not "Phase conductors"!). For three phase, four wire system, single phase is obtained by connecting the load between any two of the three line conductor, or between any one of the line conductors and the neutral conductor- depending on which connection gives us the appropriate voltage.