This thesis is to examine the difficulties my students encounter in their second language acquisition(SLA).Particular attention is paid to the marked features in English for Chinese learners—simple past verb form in morphological category and interrogatives in syntactic category.The Markedness Differential Hypothesis is recommended to explain why the difficulties occur and how the students' L1 has an effect on their L2 learning. Principles of developmental sequences and teachability hypothesis help to explain how the students could succeed in learning these forms.
