The study aims to investigate the interlanguage temporal system of college English learners in Taiwan. Given that English tense has been a difficult area for Chinese learners, it is important to look into the L2 data directly to understand where and how the learners' problems arise. As English tense and aspect are interrelated, the tense and aspect in the English interlanguage temporal system of the Chinese learners were examined as an integrated whole. Various tense-aspect forms (T-A forms) were inspected in terms of their forms, meanings, and functions. Three tasks were adopted in this cross-sectional study: a cloze passage, a composition task, and a multiple-choice test. The subjects included 129 undergraduate students of Chinese Culture University, including both non-English majors and English majors. Statistical procedures employed for data analysis included frequency count, percentage, t-tests, one-way ANOVA, etc. The results of this empirical investigation showed that the adult Chinese learners' difficulty with English tense and aspect stemmed mainly from their insufficient knowledge of English aspect and their unfamiliarity with the forms of T-A components. Most of the learners have developed a certain degree of concept of temporality in English, which might have benefited from their acquired temporal concept via L1 Mandarin. The tense of L1 Mandarin appeared to be facilitative in the learners' acquisition of the L2 English temporal system. On the other hand, English aspect was shown to be a more serious problem for the Chinese learners. The learners tended to confuse progressive aspect with nonprogressive aspect, and they had difficulty with the perfect aspect. The results also suggested that the inherent properties of verbs affected the learners' use of aspects to a certain extent. It was also shown that the Chinese learners' knowledge and application of the pragmatic functions of English T-A forms were unsatisfactory. Another revealing finding was that the processing overload of the learners was one major impediment for their correct uses of the English tenses in longer stretch of sentences and discourses. Pedagogically, the teaching of English tense and aspect should go beyond the grammatical level and the pragmatic functions of English tense and aspect should be integrated into formal instructions. More importantly, the learners should be taught to self-monitor their L2 output and be aware of their problems with English T-A forms.
