This study investigates foreground and background structures manifesting the main story event and the supportive, descriptive material of sixty EFL English narratives written by sixty senior high third-year students. These data are randomly selected from 785 narrative writings on the topic "An Unforgettabl experience" and are carefully analyzed to investigate the grounding structures and errors committed. In addition to discussing the relationship between the errors and grounding manifestations, this study proposes four pedagogicalimplications drawn from the results. The statistics show that the students tend to use complex constructions to express their thoughts, but they commit more errors in these patterns. Besides, the analysis shows that foregrounding and backgrounding can be manifested through syntactic structures, aspectual forms, tense forms, and even voice. The foregrouonding may be manifested by simple sentences, compound sentences, and main clauses of the complex sentences in the past tense. Events in the foregroundingare manifested through perfective forms conveying dynamic, telic, or punctual properties. In addition, foreground structures are more often expressed in the active voice.As for the backgrounding, it may be manifested in simple sentences, compouond sentences, and different types of dependent constructons,including initial and detachedparticiples, subordinate clauses, and embedding structures. The tenses in the backgrounding may be the future, the present, the past, the past progressive, the present perfect, and the pluperfect. Situations in the backgrounding are manifested through imperfective aspectual forms showing static, atelic, or durative features. Besides, bakcground structures may be expressed in the active or the passive voice.In the data, most of the passive expressions serve to provide background information. Moreover, it is claimed that there is a hierarchy in grounding when the structureof narratives is taken into consideration. In general, narrative structures such as introduction, body, and conclusion explicitly determine which part serves as foregrounding or backgrounding, while sequentiality, importance and expectability determine whether an event is regarded as a part of the main story line or a pieceof supportive information. In addition to showing the distrubution of types of errors, this study analyzes grammatical errors related to grounding manifestations like verbs, tenses, participles, dangling modifiers, subordinate clauses, and voice. The results indicate that the simple past tense and the simple present tense are two frequently used tenses, but many students have problems switching the present tense into the required past tense. Among the errors,some are dangling modifiers. These errors result from misunderstanding the "subject-predicate" relationship between the initial participle and the main clause. As for errors of detached participles, they may be the result of the students' not knowing that the information manifested in the detached participle is the backgroundmaterial, or not being able to use a proper participle to show the simultaneity of the event denoted in the main clause and the situation described in the detached participle. From the results of our analysis, we propose four pedagogical implications. First, for the students who have a poor command of using the more complex sentences but tend to express their thoughts with these constructions, complex constructions should be given a proper emphasis in teaching procedures. Second, since the multi-parragraph narratives have a better organiztion of writing than mono-paragraph narratives, the former with the introduction, the body, and the conclusion being separated clearly, the teacher should teach his students how to write narrative compositions.Third, from the result that the present tense and the past tense are mostfrequently wrongly used tenses, the students should be taught how to switchbetween tenses to make the narrative more vigorous and closer to the reader.Also, the fact that the complex (or relative) tenses are seldom used but often misused indicates that temporal relations between events have to be emphasized. For the students with difficulty in relative tenses, it is necessary to explain to them the chronological order of events with disocurse contexts and to teach them how to differentiate the grounding functions which the events and situations serve. Fourth, since the students have a poor command of distinguishing the function of initial or detached participles from that of corresponding main clauses, the students should be given the instruction about the usage and function of these structures in discourse.