Laboratory study was carried out to investigate the effect of acidic and alkaline characteristics of groundwater medium on three tracers (rhodamine B, eosin and potassium dichromate) commonly used for groundwater investigations. This is with the view to improving the criterion used in the selection of tracers for groundwater investigations. The factors considered are: the maximum tracer concentration, Cmax, which could be observed during the experiment, the time, tm, at which this occurs and the percentage of the tracer recovered during experiment. Others are the time, ti, of first detection of the tracer and time, tf, of total disappearance of tracer from the investigation area.A lysimeter apparatus of circular cross section with diameter, D = 45 mm was constructed and uniformly filled with coarse sand and fine gravel (each at a time). Throughout the column, steady water discharge (2.5 ml/min) at a pH value between the ranges of 5 – 8 was maintained, to carry the tracer solution through the soil column. Effluent from the bottom of the lysimeter were subjected to spectrometric analysis to determine tracer concentration.. The results suggest that rhodamine B is a suitable tracer for groundwater investigation in acidic medium but may not be suitable for alkaline medium. Values obtained for eosin showed the tracer to be good for investigation in both acidic and alkaline medium,while potassium dichromate as a tracer may be a good tracer in alkaline medium only.

In recent years, role-play activities have been widely used in the ESL/EFL classroom as an effective teaching method. This research paper aimed to investigate how group work role play activities can produce effect on students’ accuracy in speaking skill as well as how students get involved in the activities at Dong Nai Technology University. The experiment lasted in eight weeks and about fifteen students took part in this project. Oral tests were designed at the end of the experiment to measure students’ improvement. In addition, three research methods employed in my research were observation, semi-structured group interview and students’ diaries in order to perfectly understand how group work role play activities affected the participants and their attitude toward role play. The research paper came up with a positive result that all students participated in the activities and generated strong motivation in the classroom. As the research observed, the lessons with role play seem to be more interesting and attractive. In the contrast, an unexpected outcome was that role play could help improve students’ fluency but not accuracy. This paper points out both strong and weak aspects of using group work role play in improving students’ accuracy in speaking English. Based on the principal findings, conducting this research greatly affects our future practice as teachers. We believe that this research can help us respond to new challenges and become a better practitioner. As a consequence, this process would make tremendous impacts on our future practice.

Grammar teaching and learning play important roles in English acquisition. However, Vietnamese educational system still favors grammar written tests to evaluate students’ English proficiency. Therefore, students tend to learn more about language forms rather than meaningful language use. This has no doubt resulted in students’ poor communicative ability. Task-based language teaching (TBLT) is a suitable teaching approach, if applied to teach grammar for teenager students, it will not only promote their communicative ability but also instruct them to use grammar correctly and comprehensively. In other words, teachers use TBLT to balance the learning process in which learners both fulfill meaningful communicative tasks and comprehend linguistic forms. In spite of the benefits brought to learners by TBLT, they are still in theory. Therefore, in order to bridge the gap between theory and practice, it is essential to conduct a study which can prove the effectiveness of applying TBLT. As the matter of fact, the research question is ‘How do students respond to grammar learning with TBLT?’ The objective of this work can only be achieved by collecting and analyzing data, so choosing research methods has to be done accurately and carefully.

This paper indicates strong points of using the jigsaw strategy for teaching reading to teenagers. Two kinds of datasets including survey and interview provided the researcher with enough evidence in order to judge innovation. Although this is not a very successful innovation, it helps the researcher experience jigsaw reading lessons in her own teaching context. Vitally important, the innovation helps engage students in reading lessons and create meaningful interaction among them. Therefore, the research results will be applied into other reading courses at institutions in Vietnam and the researcher hopes that it might be useful for those who are interested in teaching reading through the jigsaw strategy.