一、句子成分( 一) 句子成分有主要成分和次要成分; 主要成分有主语和谓语; 次要成分有表语、宾语、定语、状语、补足语和同位语
( 二) 主语:主语是一个句子所叙述的主体,一般位于句首
但在there be结构、疑问句( 当主语不疑问词时) 和倒装句中, 主语位于谓语、 助动词或情态动词后面
主语可由名词、代词、数词、不定式、动名词、名词化的形容词和主语从句等表示
例如:During the 1990s, American country music has become more and more popular
(名词 )We often speak English in class
(代词 ) One-third of the students in this class are girls
(数词 ) To swim in the river is a great pleasure
(不定式 )Smoking does harm to the health
(动名词 ) The rich should help the poor
(名词化的形容词) When we are going to have an English test has not been decided
(主语从句 )It is necessary to master a foreign language
(it作形式主语,真正的主语为后面的不定式 ) ( 三) 谓语: 谓语说明主语所做的动作或具有的特征和状态
动词在句中作谓语,一般放在主语之后
谓语的构成如下:1、简单谓语:由一个动词或动词短语构成
如:He practices running every morning
2、复合谓语: (1) 由情态动词或其他助动词加动词原形构成
如:You may keep the book for two