Logical Subjects in Passive Sentences
The principles determining the logical subject of an infinitive become even more complicated when the infinitive phrase occurs in a passive sentence (see the SEA Site module on Passive Voice). The two sentences below illustrate how differently the logical subject is determined when the infinitive clause to repair the computer follows the "passive" verb was told as opposed to the "active" verb told.
The engineer told the technician § to repair the computer.
The engineer was told by the technician § to repair the computer.
As already noted, the logical subject of to repair in the first sentence is interpreted as the technician, which is the object of the active verb told. In the second, passive sentence, which uses the passive verb was told and a "by-phrase" (by the technician) to indicate who did the telling, the logical subject is no longer the closer object noun phrase. Instead, the logical subject is interpreted as the more distant subject noun phrase, the engineer.
Thus, passive alters the assignment of the logical subject of an infinitive. If a main verb has the property of assigning its object as the logical subject of a following infinitive, passive "reverses" that property and assigns the more distant subject of the main verb. What happens when an active verb already has the property of assigning its subject as the logical subject of an infinitive, as in the case of ask when it means "request information"? The following two sentences illustrate what happens.
The engineer asked the technician what § to repair.
The engineer was asked by the technician what § to repair.
In the first sentence, ask followed by an infinitive clause that begins with the WH-word what assigns its subject, the engineer, as the logical subject of to repair. The second sentence contains the passive verb was asked and a by-phrase to indicate who did the asking. In this sentence, the logical subject of to repair reverses from the subject to the object of the by-phrase, namely, the technician.
This reversal is the opposite of what was observed above for the told/was told pair. With tell, passive changes the logical subject from the closer object to the more distant subject. With ask (accompanied by an infinitive clause beginning with a WH-word), passive changes the logical subject from the more distant subject to the closer object of the by-phase.
Because a by-phrase is optional in a passive sentence, watch what happens when a by-phrase is omitted.
The engineer was told what § to repair.
The engineer was asked what § to repair.
In the first sentence, the passive verb was told causes the logical subject of to repair to be the more distant subject, as noted earlier. Therefore, it doesn't matter whether there is a by-phrase or not; the subject the engineer is expected to do the repairing. In the second sentence, the passive verb was asked should cause the logical subject to become the object of a by-phrase. But the sentence does not contain a by-phrase. In this case, the logical subject is interpreted as referring to whoever the object of the by-phrase would be if there were one. In other words, it is interpreted as whoever is understood from the context to have done the asking.
The above grammatical explanation and examples illustrate that the interpretation of a logical subject of an infinitive is guided by the inherent properties of the verbs that can be followed by infinitive clauses. In some cases, these verbs assign their objects as the logical subjects. In the case of promise, it always assigns its subject as the logical subject. In the case of ask, it varies in its assignment of a logical subject depending on which meaning it conveys. With the verbs say and explain, the logical subject can be understood from context, referring to someone outside the sentence. When a main verb is passive, the logical subject of the infinitive gets reversed from what it normally would be. If the logical subject would be the object of a by-phrase but the by-phrase is missing, then it is understood from context as the object of the by-phrase if there were one. Thus, interpreting logical subjects of infinitives in English is a complex process that poses a considerable challenge for many deaf students.