ASSOCIATE PRODUCTION OF W+ - AND H+/- WITH A SINGLE TOP-QUARK AT LEP-II/

Searching for a single top-quark production at LEP where the backgroun d is relatively clean is interesting. We study e(+)e(-) --> t ($) over bar b(($) over bar tb)+X cross sections at root s=200 GeV and root s= 250 GeV energies in the framework of the minimal standard model and th e extended standard model with two Higgs doublets. The resultant evalu ation of the cross sections is not very encouraging, but can be optimi stic and worth further serious studies in experiments and theories, if there exists charged Higgs with a large coupling parameter cot beta o r the design luminosity is enhanced by several orders.