They must have finished their tasks.

　　Mr Chen is my English teacher.

　　三、宾语--一直受到压制，有时"翻身农奴把歌唱"

　　宾语表示谓语动作、行为的对象，一般位于及物动词和介词的后面，受到主语的限制和制约。宾语一般由名词(短语)、宾格代词、动名词(短语)、动词不定式或从句充当，根据需要也可用it作形式宾语。宾语在被动结构中才会"翻身农奴把歌唱"。

　　1．双宾语(间接宾语＋直接宾语)

　　Mr. Smith gave him a lot of valuable advice on how to improve his writing.(him为间接宾语； advice为直接宾语)

　　2．复合宾语(宾语＋宾语补足语)

　　Doctors often advise us to pay more attention to our diets and mental health and to take regular examinations.(us为宾语； to pay more attention ... examinations为宾语补足语)

　　四、表语--最会察言观色，就看"主子"脸色

　　表语一般位于系动词(如be, become, get, look, grow, turn, seem等)之后，用以说明主语这个"主子"的身份、特征和状态，一般由名词、名词性代词、形容词、分词、数词、不定式(短语)、动名词、介词短语、副词及表语从句等充当。

　　The cultural background of China is totally different from that of the US.(形容词作表语)

　　My suggestion is that we should start at once.(从句作表语)

　　五、定语--鞍前马后搞服务，全心全意勤务兵

　　修饰或限定名词或代词的词、短语或从句被称为定语。定语服务于它所修饰或限定的名词或代词，可由形容词、数词、形容词性物主代词、介词短语、非谓语动词(短语)或定语从句等充当。定语有前置和后置两种情况，如短语结构、从句等作定语时，常置于被修饰词之后。

　　The beautiful girl is her daughter. (形容词和形容词性物主代词作定语)

　　The building being repaired is our library.(非谓语动词作后置定语)

　　六、状语--行踪飘忽不定，却对动词"情有独钟"

修饰动词、形容词、副词或整个句子，说明动作或状态特征的句子成分叫作状语。