The large kinetic zero-point motion of (4)He molecules has been properly taken into account in the significant structure theory of liquids in order to describe the liquidity of liquid (4)He. The Debye and the Bose-Einstein partition functions are used for the solid-like molecules of the normal fluid component and for the whole gas-like molecules, respectively. The solid-like molecules of the superfluid component are considered as ground state molecules without having positional degeneracies. The Bragg-Williams approximation of an order/disorder phase transition has been applied to the lambda transition of liquid (4)He. Thermodynamic and surface properties of liquid (4)He have been calculated up to the critical point. The results are satisfactory when compared with the observed values.