神马作文网独立主格结构什么时候用完成时?
来源：学生作业帮 编辑：神马作文网作业帮 分类：英语作业 时间：2024/09/21 19:30:14
独立主格结构什么时候用完成时?
如这个题：
All flights ______ because of the snowstorm,many passengers could do nothing but take the train.
A）had been canceled B）have been canceled
C）were canceled D）having been canceled
因为风雪,所有航班都被取消,许多旅客别无它法,只得乘火车.(D)
All things ______,the planned trip will have to be called off.
A）considered B）be considered
C）considering D）having considered
考虑了方方面面之后,原来计划好的旅行不得不取消了.(A）
为什么前者要用完成时而后者不用?
如这个题：
All flights ______ because of the snowstorm,many passengers could do nothing but take the train.
A）had been canceled B）have been canceled
C）were canceled D）having been canceled
因为风雪,所有航班都被取消,许多旅客别无它法,只得乘火车.(D)
All things ______,the planned trip will have to be called off.
A）considered B）be considered
C）considering D）having considered
考虑了方方面面之后,原来计划好的旅行不得不取消了.(A）
为什么前者要用完成时而后者不用?
第一,当从句的谓语发生的动作给主句造成一定的影响,有了一个结果.如：第一道题可改写成：Many passengers could do nothing but take the train because all flights has been canceled.
第二,当从句的动作先于主句的发生,就要用到having done/having been done.
在第二道题中,all things跟consider是动宾关系（被动）,而不存在第一题里的关系.所以不用完成时.
第二,当从句的动作先于主句的发生,就要用到having done/having been done.
在第二道题中,all things跟consider是动宾关系（被动）,而不存在第一题里的关系.所以不用完成时.