| This study explored the effectiveness of the timing of grammar instruction theoretically known as isolated and integrated form-focused instruction(FFI),while investigating the differential effects of those two types on junior high students’ learning of different grammatical structures(i.e.,simple past and comparative).Timing of FFI was originally proposed by Spada and Lightbown(2008).Both isolated and integrated FFI are used in classrooms that are mainly communicative.They differ in that isolated FFI takes place separately from communicative activities,while integrated FFI occurs during communicative activities.A total of 124 second-year junior high school learners from three intact classes were randomly assigned into three groups: a control group,which received regular classroom instruction,and two experimental groups,which received isolated or integrated FFI on the two target features.A total of four 80-minute treatment sessions(i.e.,two for each experimental group)took place.A quasi-experimental,pretest/posttest/delayed posttest design was adopted for this comparative study in order to measure language development.Language measures included an error correction task and an oral elicited imitation task.Students were tested with the two tasks before,immediately after,and three weeks after the treatment.The results obtained from a mixed-design ANOVA indicated that the learners in the two experimental groups outperformed the control group and made significant gains on the two language measures.A dependent samples t-test revealed that the two target structures responded differentially to the timing of form-focused instruction.While the simple past is more likely to be affected by isolated form-focused instruction on both the error correction test and the oral elicited imitation test,the comparative is more likely to be affected by integrated form-focused instruction on the oral elicited imitation test and,to a lesser degree,on the error correction test.The research outcomes offer some implications for EFL methodology,clearly indicating practicability of the two types of instruction on different grammatical structures. |