Technology has become an essential part of education today, and learning environment has changed from that of many years ago; students need to use technology as an alternative effective learning tool for learning English language as a foreign language (EFL). Most of current studies in the educational use of social media seem to pay more attention to the students' use of Facebook in learning. This research explores 14 university learners use of Facebook group and it mainly focuses on lecturers' role in Facebook group. This qualitative study involved observation and some interview questions. Current findings highlight that there are potential benefits to using Facebook for learning with reference that these students still need a guideline and support from their lecturers to learn English via Facebook. This paper suggests that considerable students' content knowledge of educational technology as Facebook is required to improve their learning. This study hopes to add and expand current body of knowledge about learning English in relation to Facebook used in English foreign language context. 

SUMMARY

This thesis entitled comprises four chapters and ends with alist of references.

The first chapter covers the literature up to date of the reaction of nucleophilic substitution reactions and their different mechanisms.then describes .of preparation of the methods

the procedure used to determina the rate constant for the reaction and kinetic data

then deals the discussion and interpretation of the results from the above mentioned reaction .

application of Hammett relationship . and application of Bronsted equation

Previous studies have established that male and female speakers differ in their production of foreign language (FL) vowels due to biological differences in the vocal tract. These differences present a challenge when subjects recruited for an instrumental analysis of speech sounds include speakers of both genders. Most previous studies, therefore, focus on only one gender to avoid the problem of biological differences between males and females. However, different gender groups may perform differently in speaking tasks as their language experience may be influenced by other social factors. Therefore, the aim of this study is to assess the differences between Libyan male and female speakers in the production of English vowels, by examining the data with and without the use of normalization to determine the most difficult English vowels for Libyan male and female speakers. To achieve this goal, seventy Libyan participants (35 male and 35 female) were recruited to perform a speech production task of eleven English vowels embedded in carrier sentences. The data were collected and analyzed using PRAAT to extract the F1 and F2 formant frequencies for each vowel and to calculate the Euclidean distance (ED) of the English vowels produced by using the centroid as the reference point. With the unnormalized data, more overlaps were found for the male speakers when compared to the female speakers as the vowel space were more centred for the males compared to the females. With the unnormalized data, different pairs of vowel contrasts were identified as potentially problematic. However, with the normalized data, better categorical distinction is found in general. Only three vowels emerged as potentially problematic as the other pairs could potentially be disambiguated using vowel duration as a cue. The study demonstrated the utility of the Lobanov method for normalizing speech data to reduce variability associated to gender differences. The efficacy of the Lobanov method of normalization remains to be tested further to verify if the predictions made about difficult vowel pairs for Libyan EFL learners are indeed attested in their discrimination of these vowel pairs in future research. 

Group work is believed to be one of the possible solutions to the problem of dealing with large number of students within one speaking class. However, how students perceive group work in their EFL speaking classes is an area that needs to be researched. This study looks at how students perceive group work in their speaking classes and their preference of being given a specific role in a given speaking task that involves working in a group. A questionnaire has been distributed to 42 students to highlight their perceptions towards group work. Results from this study revealed that EFL students seem to like the idea of working in groups in their speaking classes as they reported a number of benefits that they gain when they work in groups, for example, they feel more independent, they have a chance to share ideas, and they speak English in most of the time in the class. However, a number of drawbacks have been also reported by the students, for example, the domination of one student in the group, some students find it difficult to work in a group of mixed gender, and low level students sometimes feel frustrated to work in group.