Our former study [1] has shown that maximum likelihood (ML) based frame selection, which selects reliable frames from a high resolution along the time axis, helps to improve the discrimination between phonemes. In this paper, we present our recent research on single frame selection for a phoneme classification task. A new single selection, which only selects one frame for one state in an Hidden Markov Model (HMM), is proposed. The new technique takes likelihoods of frames and their positions in a phoneme segment into account at the same time, and selects very few frames to represent the spectral evolution of the phoneme. Furthermore, we also show that for a low model complexity, a phoneme model trained by selected frames is more discriminative than a model using all frames.