In the first order of perturbation theory, expressions were obtained for the components of the dynamic polarizability tensor of a pair of atoms interacting at large separations R, via the dipole-dipole mechanism, which coincide with first-order terms of the classical dipole-induced-dipole model (the DID model). For a pair of different atoms, the contributions proportional to R-3 to the induced polarizability were shown to result entirely from changes in wave functions, and, consequently, in transition dipole moments. In addition, the level shifts caused by the resonance interaction have to be taken into account in the case of identical atoms. In both cases, induced polarizability arises due to redistribution of the oscillator strengths among transitions from the ground state to molecular terms Σ and II correlated with the excited states of isolated atoms. Expressions were obtained for the changes in the probabilities of electric-dipole transitions (the oscillator strengths) in a pair of atoms caused by the dipole-dipole interaction.