ENGLISH GRAMMAR. Government & Binding

Theta-roles and clause structure
The theta-criterion functions as a tool for syntactic analysis in that it guides us in determining the structural relations in a sentence.
a. Thelma believes this story.
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b. Thelma believes Louise.
1 2
c. Thelma believes [that Louise has abandoned her husband].
c´. Thelma believes [that Louise has abandoned her husband].
1 2
[ 1 2 ].

The first building blocks of the sentence: the verb and its argument (s).
(1) d. Thelma believes Louise to have abandoned her husband.
Semantically (1d) is very close in interpretation to (1c), where believes takes a clausal complement and in which Louise is an argument of abandoned. In (1d) the verb believe also has thematic roles, as in previous sentences, and these are assigned to its subject Thelma and to its complement, Louise to have abandoned her husband. Cf.:
d´. Thelma believes [Louise to have abandoned her husband].
2
[ 1 2 ].
c´. Thelma believes [that Louise has abandoned her husband].
1 2
[ 1 2 ].

Locality and thematic structure
The arguments required by a verb tend to be realized in the vicinity of the particular verb. There is a locality requirement on the realization of the argument structure.
(2) a. [Mary] showed [her sister] [ why [Louise] had destroyed [the painting]]
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b.*[Mary] showed [her sister] [the painting][ why [Louise] had destroyed]
1 2 3 ?
1 2?
(2a) is a complex sentence: it contains an embedded clause. The verb show is associated with three thematic roles. Within the embedded clause the verb destroy takes two arguments. (2b) is ungrammatical: the verb destroy is missing one argument.

(3) a. Which painting did Mary say that Louise had destroyed?
b. Who did Mary say had destroyed the painting?
It looks as if arguments moved away from the verb which assigns them a theta-role, the theta-assigner, to positions outside the sentence in which the theta-assigner appears. In (3a) which painting appears to the extreme left of the sentence; it is closer to the verb say that to the verb destroyed. Yet, which painting is the THEME argument of destroyed.

A verb has an argument structure associated with it. The arguments are either realized in the same sentence as the verb with which they are associated or else they are moved away from the verb, leaving an open slot. Cf.
(4) a. Mary said [that Louise had destroyed the painting].
b. Which painting did Mary say [that Louise had destroyed [―]]?
c. Who did Mary say [[―] had destroyed the painting]?
In (3a) the Od of destroyed, which painting, is extracted from the embedded clause; in (3b) the S of the embedded clause is extracted. The position from which a constituent moves is called its extraction site; the position to which a constituent moves is called its landing site.

Implicit arguments
The arguments of the verb are always realized explicitly or overtly. Cf.:
(5) a. She trusted Bill.
b. *Trusted Bill.
c. Thelma was wondering whether she should trust Bill.
d. *Thelma was wondering whether should trust Bill.
(5a) is a grammatical sentence. (5b) shows that we cannot omit the first argument of trust.
(5) e. Trust 1: she
2: Bill
Each argument bears one theta-role, therefore, the NP, Thelma, cannot simultaneously realize as an argument of trust and an argument of wonder.

(5) c. Thelma was wondering [whether she should trust Bill].
f. Thelma was wondering [whether to trust Bill].
In (5f) as in (5c) trust selects the NP Bill as one of its complements. The sentence is grammatical even though one argument of trust seems to be missing. In (5f) the second argument of trust is implicit: it is Thelma. The verb trust does have two arguments: one is overtly realized as Bill; the other is understood as non-overt. The argument is present in the abstract representation of the sentence which determines its interpretation, but it is not present in the phonetic string. Such abstract or non-overt arguments can be presented by the symbol ec (empty category).

(5) g. Thelmai was wondering [whether __ eci to trust Bill].
1 2
[1 2]
Representation (5g) shows that trust has one argument (Bill) and one non-overt one (ec). The non-overt element ‘ec’ is referentially dependent on Thelma, the overt argument. The dependency is represented by a subscript^ Thelma and ec are co-indexed.
(6) a. I promised John a new bicycle.
AGENT BENEFICIARY THEME
b. I promised John [that I would buy a new bicycle].
1 2 3
1 2

(7) a. I promised John [to buy a new bicycle]. Cf.:
I promised John [that I would buy a new bicycle].
b. Ii promised John [eci to buy a new bicycle].
In case of (7a) the infinitival clause contains a non-overt subject, which is controlled by the subject I in the matrix clause. Cf. also:
(8) a. I asked John a question.
b. I asked John if he would buy a new bicycle.
c. I asked John to buy a new bicycle.
d´. I asked Johni [eci to buy a new bicycle].
1 2 3
1 2

Do all verbs assign theta-roles?
(9) a. Thelma bought a new bicycle.
b. Thelma has bought a new bicycle.
c. Thelma is buying a new bicycle.
d. Thelma will buy a new bicycle.
Auxiliaries are treated as case inflections and therefore cannot assign theta-roles and accordingly take arguments.

Do only verbs assign theta-roles?
Verbs, nouns, adjectives and prepositions can assign thematic roles.
(10) a. They announced [that Thelma has arrived].
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1
b. They announced [Thelma’s arrival].
1 2
[ 1 ]
In (10b) the complement of announce is Thelma’s arrival (NP). In this NP, Thelma has a semantic relation which is parallel to the relation of Thelma to arrived in (10a).

Expletive subjects. Expletive it.
(11) a. [That Louise had abandoned the project] surprised everyone.
1 2
[ 1 2]
b. It surprised everyone [that Louise had abandoned the project].
? 1 2
1 2
(11b) contains an additional NP, it. The clause is shifted to the right. And the subject position is occupied by it, which is not used as a referential unit/ It does not have a referent. A non-referential element like it in (11b), which seems to function as a mere filler for the subject position and which fails to contribute to the semantics of the sentence, is called expletive.