本研究的目的是基于标记性差异假设，调查显性教学与隐性教学对初中生语法学习效果的差异性研究，并研究其对不同能力水平的英语学习者的效果。 实验过程持续了一个半月，共有三种语法规则。第一个是祈使句，代表的是在汉语里和英语里语法规则一样的语法；第二个是反义疑问句，代表的是汉语和英语里都有但是规则不相同的语法；第三个是第三人称单数，代表的是汉语里没有，只在英语里有的语法。实验对象是初一两个班上的96名学生。两个班分别采用显性教学和隐性教学，两个班都由同一老师执教。其中，隐性教学班在后测之后会填写一份关于学习语法过程中意识水平的问卷。 独立样本检测结果表明，在祈使句的教学中，显性教学和隐性教学中并没有显著差异。在反义疑问句和单数第三人称的教学中，显隐性教学存在着显著差异。在反义疑问句的教学中，显性教学比隐性性教学更有效。在第三人称教学中，隐性教学比显性教学更有效。由此可得出，在学习英语和汉语里都存在但略有不同的语法时，采用显性语法更有效。在学习仅存在于英语中的语法时，隐性语法更有效。语法类型和教学方法对语法学习并没有产生互动效果。 该研究结论表明，语法类型不同显性教学和隐性教学所产生的的语法学习效果也不同。该研究结果对我国英语学习者的语法学习及我国英语语法教学都提供了有益的启示。强调了初中生的个体能力差异，研究所得数据对英语新课程改革提供了一定的依据。

The objective of the study is to investigate the effectiveness of explicit and implicit instruction in English grammar based on Markedness differential hypothesis within the actual junior high school English classroom, and examine the effects for middle school especially junior high school EFL(English as a Foreign Language) learners with different English proficiency levels in China. The experiment procedure lasted one and half month owing to three grammatical structures, i.e. the grammatical structure which is the same as Chinese (the imperative sentence), the grammatical structure which is different from Chinese(the question tag), and the unique grammar in English( third person singular). The subjects were 96 students from grade seven. The teacher gave the same treatment to both the explicit and implicit classes under the same condition. And the two classes received a questionnaire about the awareness of grammar after the post test. The results of the t-test showed that firstly no significant difference was found between explicit instruction and implicit instruction on the post test of imperative sentence.There was significant difference found between explicit and implicit instruction on the the post test of question tag and third person singular. It could be concluded that implicit instruction outperformed explicit instruction in the learning of the unique grammar in English. And explicit instruction outperformed implicit instruction in the learning of the grammatical structure which is different from Chinese. Grammar type and teaching instruction did not have interactive effect on grammar learning. The study concludes that the effects of explicit and implicit instructions vary when applied to different grammatical rules. The thesis provides beneficial implications to both Chinese English learners and the grammar teaching of second language. It emphasizes the individual differences of junior high school students, which provides data for the reform of English curriculum.