This study aims to find out whether there are any statistically significant differences in participants' achievements on three different types of instruction: computer-based instruction, teacher-driven instruction, and teacher-driven grammar supported by computer-based instruction. Each type of instruction follows the deductive approach. The sample of the study consists of 50 learners of English enrolled in a preparatory course for a high-stake language exam conducted in Turkey. The effectiveness is compared based on the results obtained from the post-test and the delayed post-test, which is conducted five weeks later. The participants instructed by using both computer-based and teacher-driven grammar instruction supported by computer-based materials score higher than those who receive traditional instruction. Moreover, supporting teacher-driven instruction with computer-based materials in learning adverbial clauses can lead to higher achievement through taking practice beyond the classroom.