学文网用好非谓语动词，找到其逻辑主语是关键，下文结合例句和考题讨论非谓语动词的逻辑主语的位置。
一、句子的主语
非谓语动词作状语、主语补足语时，其逻辑主语为句子的主语。如：
Charles Babbage is generally considered to have invented the first computer.（to have invented为句子的主语补足语，它的逻辑主语是Charles Babbage，该动作在谓语动词所示动作之前发生，用完成式）
例1 _____ an important decision more on emotion than on reason，you will regret it sooner or later.
A. Based B. Basing C. Base D. To base
解析：选B。动词base与逻辑主语you之间构成主动关系，因此用现在分词作状语。注意：（sb.）base A on B相当于A is based on B。
例2 Having finished her project，she was invited by the school _____ to the new students.
A. speaking B. having spoken
C. to speak D. to have spoken
解析：选C。to speak作逻辑主语she的补足语，注意搭配invite sb. to do sth.。
二、句子的宾语
非谓语动词作宾语补足语，该宾语就是非谓语动词的逻辑主语。如：
She stood in front of him，with her eyes fixed on his face.（fixed的逻辑主语是介词with的宾语her eyes，注意搭配fix one’s eyes on sth.）
例3 Michael put up a picture of Yao Ming beside the bed to keep himself _____ of his own dreams.
A. reminding B. to remind
C. reminded D. remind
解析：选C。reminded作宾语补足语，表示状态，逻辑主语himself和reminded为被动关系。
例4 I looked up and noticed a snake _____ its way up the tree to catch its breakfast.
A. to wind B. wind C. winding D. wound
解析：选C。此题考查现在分词作宾语补足语。winding its way与句子的宾语snake之间为主动关系，且此动作正在进行。
三、修饰的先行词
非谓语动词作定语时，其逻辑主语为该词修饰的先行词。如：
The people operating these factories are deeply concerned about the environment.（operating的逻辑主语为先行词the people，它们之间是主动关系）
His first book to be published next month is expected to be a success.（不定式to be published表示将来的动作，其逻辑主语是his first book）
例5 Recently a survey _____ prices of the same goods in two different supermarkets has caused heated debate among citizens.
A. compared B. comparing
C. compares D. being compared
解析：选B。非谓语动词作定语，和被修饰的survey是主动关系，因此用-ing形式。
例6 We’re having a meeting in half an hour. The decision _____ at the meeting will influence the future of our company.
A. to be made B. being made
C. made D. having been made
解析：选A。分析句子结构可知，空白处为后置定语，根据will influence确定为将来动作，且与被修饰的名词是逻辑上的被动关系。
例7 The witnesses _____ by the police just now gave very different descriptions of the fight.
A. questioned B. being questioned
C. to be questioned D. having questioned
解析：选A。首先判断此处需要一个非谓语动词，作witnesses的后置定语，question与witnesses之间为被动关系，根据标志词just now可知动作question已经完成。
四、***的逻辑主语
非谓语部分常作状语，其逻辑主语与主句的主语不同，构成***主格结构。如：
All the work done，you can have a rest now.（done的逻辑主语是work，主句主语是you）
He suggested going for a picnic，Mary to provide the food.（不定式表示将来的动作，逻辑主语是Mary，主句主语是he）
例8 Bats are surprisingly long-lived creatures，some _____ a life span of around 20 years.
A. having B. had C. have D. to have
解析：选A。因为句中已有谓语动词are，所以该空要填非谓语动词；因为逻辑主语与have为主动关系，所以用 -ing形式。
例9 The party will be held in the garden，weather _____.
A. permitting B. to permit
C. permitted D. permit
解析：选A。由于主句的主语party与weather不一致，所以weather作permitting的逻辑主语，构成***主格结构。两者为主动关系，用现在分词。
此外，动名词复合结构也有自己***的逻辑主语。如：
Many trees were cut down and that resulted in the village being buried by sand. （the village可用the village’s代替，是being buried的逻辑主语）
Mary’s not passing the driving test made her very upset. （动名词复合结构作句子的主语，Mary’s不宜用Mary代替）
五、无逻辑主语
非谓语动词在句中作主语、宾语和表语时，相当于名词，常常没有逻辑主语。
1. To see is to believe.（非谓语动词作主语和表语）
2. His plan is about expanding the business.（非谓语动词作宾语）
例10 No matter how bright a talker you are，there are times when it’s better _____ silent.
A. remain B. be remaining
C. having remained D. to remain
解析：选D。it作形式主语，真正的主语是后面的不定式to remain silent。 （责任编校/彭益）
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