Teaching formulaic sequences in an English-language class: The effects of explicit instruction versus coursebook instruction

This study investigates the relative effectiveness of different teaching approaches on the learning of formulaic sequences. Three comparisons were made in this study: the effects of explicit teaching of formulaic sequences versus teaching embedded in traditional coursebook instruction, the effects of the degree of salience of the sequences in the coursebook on learning, and the effects of explicit teaching of formulaic sequences with context versus teaching without context. Sixtynine formulaic sequences occurring in an English as a Foreign Language (EFL) coursebook were selected for the study. The participants were 60 low-proficiency university students majoring in technology in Vietnam. Participants were quasirandomly assigned to one of three groups: control, no-context learning, and sentence-context learning. Learning was measured by two multiple-choice tests of receptive knowledge of form and meaning. Findings indicated that although explicit instruction was effective, the degree of salience in traditional coursebook instruction had no significant effects on learning formulaic sequences. Explicit teaching combined with incidental exposure to formulaic sequences in the coursebook was superior to the traditional coursebook instruction approach in the classroom setting. Furthermore, the results from explicit instruction with context sentences did not differ significantly from those of instruction without context. Explanations for the findings and pedagogical applications are offered

Instability of the Time Dependent Horava-Witten Model

We consider scalar perturbations in the time-dependent Ho\u{r}ava-Witten Model in order to probe its stability. We show that during the non-singular epoque the model evolves without instabilities until it encounters the curvature singularity where a big crunch is supposed to occur. We compute the frequencies of the scalar field oscillation during the stable period and show how the oscillations can be used to prove the presence of such a singularity.Comment: 12 pages, 4 figures. References added. Some comments clarified. Accepted in Phys. Rev.