怎样区分that 做指示代词还是引导定语从句Genetic engineering introduces into food genes that are not present naturally,can not be introduced through conventional breeding and may have unknown health effects that should be investigated
来源：学生作业帮助网 编辑：六六作业网 时间：2024/12/21 01:31:18
怎样区分that 做指示代词还是引导定语从句Genetic engineering introduces into food genes that are not present naturally,can not be introduced through conventional breeding and may have unknown health effects that should be investigated
怎样区分that 做指示代词还是引导定语从句
Genetic engineering introduces into food genes that are not present naturally,can not be introduced through conventional breeding and may have unknown health effects that should be investigated before the food is sold to the public.句子里面的最后一个that参考书中说是指示代词,指代food genes,不明白为什么不是做effects的定语,怎样区分呢
怎样区分that 做指示代词还是引导定语从句Genetic engineering introduces into food genes that are not present naturally,can not be introduced through conventional breeding and may have unknown health effects that should be investigated
问题:不明白为什么不是做effects的定语,怎样区分呢
Answer:
(1)从语法上讲可以把"effects"作为后一个"that"从句所修饰的先行词,但从语意上却行不通"需要被研究(调查)的健康效果".什么话?效果/影响是产生的,不是被研究/调查出来的.显然构不成逻辑上的修饰关系.
(2)全句的句构很清晰:主句+定从(1)和定从(2)
定从(1)中的谓语由三个并列谓语构成,它们的共同主语都是由关系词that来充当
定从(2)句构简单,只不过句中多了一个由before 引导的时间状语从句作其状语
注:定语从句的语法功能就是做修饰成分,当一个先行词由多个定语从句来修饰,或在间隔式定语从句中,定语从句修饰谁,要从句意和语法两个方面来考虑.在符合语法规则却又能与多个先行词构成逻辑上的修饰关系的定句从句是不存在的.即使存在也是歧义句是病句.
If you still feel confused ,leave a message please
.两个that都在句中充当定语从句的引导词
是不是定语从句根据主句成分是否残缺判断
而这个引导词指代的就是它前面的那个名词
也就是说that作为指示代词和定语并不矛盾