Las diferencias entre el pretérito perfecto simple y el imperfecto son uno de los temas más complejos de la lengua española, no sólo para el estudiante, sino para el profesor, puesto que sistematizar los casos y hacerlos fácilmente comprensibles al alumno es tarea difícil. Los profesores de lengua, cuyas investigaciones han dado lugar a una serie de teorías y de corrientes metodológicas y didácticas que permiten enfocar la enseñanza de una lengua extranjera de manera muy distinta a como se hacía tradicionalmente. Vamos a repasar muy brevemente cuáles son estas teorías.

En primer lugar es necesario señalar en qué consiste el aprendizaje de una segunda lengua:

"El aprendizaje de una segunda lengua (L2) es el

The aim of the research is to measure the relationship and effect of the application of total production maintenance TPM in the operational strategy, as it is considered one of the most important strategies for the process of restoring production losses because of inefficient equipment. Competitive edge in the global market by upgrading the operational strategies of OS in the application of TPM in those institutions that apply both H-OS-oriented and P-OS-oriented strategies where the strategy has been identified as a critical success factor. The aim of this study is to attempt to consider the application of comprehensive productive maintenance in industrial establishments

Tench is a cyprinid fish that has undergone human-induced translocations. The natural populations of the species are on the decline due to habitat loss and spawning grounds degradation. The genetic diversity of seven natural populations was investigated to establish the genetic knowledge base for successful conservation efforts and for selective breeding. Twelve microsatellite markers, the sequencing of a 615 bp section of mtDNA (Cytb) and PCR-RFLP analysis of two nuclear markers (Act) and (RpS7) were used to analyze the genetic variation and structure among 175 individuals. All microsatellite loci were found to have moderate levels of polymorphism. The pairwise Fst values between population pairings were moderate; the populations w

This research involves the synthesis of some sulphanyl benzimidazole derivatives (Ia-c), which were prepared from reaction of 2-mercaptobenzimidazole substituted benzyl halide, and structures were identified by spectral methods[FTIR, 1H-NMR and 13C-NMR].These compounds were investigated as corrosion inhibitors for carbon steel in 1M H2SO4 solution using weight loss, potentiostatic polarization methods; obtained results showed that the sulphanyl benzimidazole derivatives retard both cathodic and anodic reactions in acidic media, by virtue of adsorption on the carbon steel surface. This adsorption obeyed Langmuir’s adsorption isotherm. The inhibition efficiency of (Ia-c) ranging between (65-92) %. By using different Ib derivative conc

Back ground: Chronic total occlusion (CTO) of coronary arteries remains one of the most challenging lesion subsets in interventional cardiology even with the development of medical devices and operator expertise. Successful revascularization results in improved in angina status ,increased exercise capacity and reduces the need for lat CABG surgery .
Objectives: This study sought to determine the overall procedural success rate of percutaneous coronary intervention (PCI) for CTOs and to examine the relation between variables such as; patients’ characteristics, risk factors, lesion characteristics and procedural success rate.
Methods: In this study ,clinical and coronary angiography data of (80) patients with CTO who underwent PCI

Many behavioral researchers pointed out the importance of relaxation techniques in the treatment of different psychological disorders where find  the importance of these techniques in reducing anxiety and stress and the resulted of behaviors and habits, with the development of these techniques are being used to gain public health, whether mental health or physical or mentality, and one of these techniques is music therapy that reduces tension and anxiety and operates a state of relaxation, which is used in the treatment of  patients of dental clinic.                        

Re

The transition of professionals between different sectors is considered as one of sources of
acquisition of technology and will lead to add the practical experience to them. This experience
depending on different factors like: the scientific degree and practical experience by the
professionals, the technology possessed by the transferor sector, the duration that spent by
experienced in transferor sector, the type of work performed by professional….etc.
The research aims to verify the affect of these factors in technology transfer process.
Research reached that the technology transfer process which is depending on the Iraqi competencies
in work is unsatisfied level between Iraqi organizations because there are dif

The present study analyzes the violation of the strategies of conversation in two English plays namely Richard II and King Lear. The present study tries to achieve the following goals: 1. showing how the strategies of real conversation can be applied to conversation in plays. 2. analyzing how the characters communicate with each other to discover how Shakespeare violates the strategies of conversation in depicting his characters. The study has been conducted on the bases of the following hypotheses:

1. The strategies of conversation which are derived from the study of natural conversation can be applied to conversation in drama with some modification for dramatic purposes.

The study aimed to identify career engagement among school principals, the researcher used descriptive approach and reached the study sample (230) school, principals. The researcher instruments used: career engagement, has been checked and face validity, and construction and consistency of the instruments using internal consistency Cronbach's alpha The study came to the following findings: - The degree of career engagement among school principals was (29.0200) this refers to a higher level, compared with the theoretical average of (27) and the study showed that the results showed no significant statistical differences between school principals in the level of career engagement due to the variable sex.