【正确答案】(1)Influence of the first language. One of the features of second language acquisition (SLA) is that first language can exert influence. The process is called language transfer.
(2)A natural sequence of Development. The second feature is that all L2 learners, no matter what their L1 is, follow a natural, fixed order in learning the grammar of the L2.
(3)Irregular learner errors. The third feature is that learner errors are not regular. They may make an error in some contexts but not in others.
(4)Learner difference. Learner factors may influence the mastery of L2.
(5)Learner strategies. Learner strategies are used: learning strategies, production strategies, and communication strategies.
(6)Formal instruction. Formal instruction usually takes place in the classroom and the L2 is taught systematically with syllabus and textbooks.
(7)The early stages. The early stage of L2 acquisition in naturalistic setting is often characterized by a silent period, but the use of formulaic speech, and by structural and semantic simplification. At this stage, both structural and semantic simplifications take place.

【答案解析】[解析] 此题考查的是考生对二语习得特征的了解。