Even their most ardent champions concede that no less than a technical or scientific breakthrough is necessary before solar cells can meet the goal of providing one percent of the nation's energy needs.
242. Even their most ardent champions concede that no less than a technical or scientific breakthrough is necessary before solar cells can meet the goal of providing one percent of the nation's energy needs. (A) that no less than a technical or scientific breakthrough is necessary (B) that nothing other than a technical or scientific breakthrough is needed (C) that a technical or scientific breakthrough is necessary (D) the necessity for an occurrence of a technical or scientific breakthrough (E) the necessity for a technical or scientific breakthrough occurring