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Embedded Clauses in TAG. S. NP VP. V S-bar. S. COMP NP VP. We think that they have left. Embedded Clauses. Matrix Clause. Embedded Clause. The cat seems to be out of the bag. There seems to be a problem. That seems to be my husband.
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S NP VP VS-bar S COMPNPVP We thinkthat they have left. Embedded Clauses Matrix Clause Embedded Clause
The cat seems to be out of the bag. There seems to be a problem. That seems to be my husband. The doctor seemed to examine Sam. Sam seemed to be examined by the doctor. The cat tried to be out of the bag. *There tried to be a problem. That tried to be my husband. The doctor tried to examine Sam. Sam tried to be examined by the doctor. How we know that the semantic role assignments are different with Seem and Try
S S NP VP NP VP VS-bar VVP-bar S VP COMPNPVP COMP It seemsthat they have left. They seemto have left. Raising to subject
S Two ways to represent that “seem” and “leave” share a subject. NP VP VVP-bar Subj they Verb seem Complement subj verb leave VP COMP They seemto have left. S NP VP VS NP VP They seem e to have left.
Comparison • Second method: • Allow empty strings as terminal nodes in the tree. • An empty string needs to take the place of the missing subject of the lower clause. • The empty string is linked to the subject of the main clause to show that the main and embedded clauses share a subject. • The tree represents: word order, constituent structure, grammatical relations, semantic roles. • First method: • No empty strings in the tree. • The tree represents only word order and constituent structure. • Grammatical relations and semantic roles are represented in a separate structure. • Structure sharing in the representation of grammatical relations shows that the two verbs share a subject. • Is one method simpler than the other? • No. Both methods have to represent word order, semantic relations, grammatical relations, and semantic roles. • People who argue that one is simpler are usually wrong – they don’t know how to count steps in a derivation.
S Two ways to represent that “try” and “leave” share a subject. NP VP VVP-bar Subj they Verb seem Complement subj verb leave VP COMP They try to leave. S PRO is an empty string, but not the same kind of empty string as e Coindexing indicates that PRO refers to “they”. NP VP VS NP VP They(i) try PRO(i)to leave.
S NP VP Adjunction site V AP John to be happy “Seem” type verbs in TAG VP V VP seem Auxiliary Tree Initial Tree These trees represent the number of arguments for each verb: “Seem” has one argument, represented as a VP. “To be happy” has one argument, “John”.
VP V VP Adjunction site seem S NP VP VP V AP to be happy John
VP VP S S NP NP VP V VP V VP seems seem V AP V AP to be happy to be happy John John Adjunction VP This tree shows word order and constituent structure. It also shows that “John” is the subject of “seem.” It doesn’t show that “John” is the subject of “to be happy.”
S S NP VP Adjunction site NP VP TO VP V S PRO leave John tried “Try” type verbs in TAG Initial Tree Auxiliary Tree These trees show the number of arguments for each verb: “Try” has two arguments. “Leave” has one argument.
S S NP VP Adjunction site NP VP TO VP V S PRO leave John tried S
S S NP VP Adjunction site NP VP TO VP V S PRO leave John tried S
S S NP VP NP VP TO VP V PRO leave John tried Adjunction is only allowed at the top S node so as not to mess up compositional semantics: After you put together “try to leave” you don’t want to have to take it apart again by inserting another verb like “expected” as in: John tried to expect to leave. Inserting “seem” into the middle of the tree doesn’t require you to disassemble any of the semantic pieces that were already assembled?