Idioms abound in both spoken and written English, yet they present a particularly thorny problem in foreign language learning. One of the reasons for this difficulty is second language learners' ignorance of the holistic nature of English idioms. Based on computerized reading tasks, the present study probes the effects of using electronic glosses during Chinese English-as-a-Foreign-Language (EFL) learners' acquisition of idioms, examining the roles that text enhancement, task type, and task condition might play in the noticing and acquisition of these lexical items. The results show that text enhancement could effectively draw learners' attention to the target idioms and was conducive to learning these lexical items. Subjects who were forewarned of an upcoming idiom test not only noticed significantly more target idioms than subjects who were not forewarned of the test but also showed better retention of the idioms. Finally, compared with the subjects who undertook true/false reading comprehension tasks, the subjects who completed translation tasks noticed significantly more target idioms and scored significantly higher on the idiom test.