Practical Grammar 9

Complement Clauses

Next, we come to the exciting topic of complement (= subordinate) clauses. Here are two examples:

(1) Fred thought that Lilly disappeared
(2) Fred asked whether Lilly disappeared

There is nothing really special about these structures. As with prepositional phrases, we need

1. lexical items for the new verbs
2. lexical items for the two complementizers that and whether
3. two new phrase structure rules.

We make the following assumptions:

1. that and whether belong to the part of speech C (= complementizer).
2. A complementizer combines with a following S to form another S.
3. The C and the lower S are co-heads of the upper S.
4. You need to add a new VP rule which allows a VP to consist of a V and an S. The S bears the GF COMP.
5. Complementizers have no PRED value.

Exercise 9

1. Open Grammar Grammar 9 - 2026-02-04
2. Implement the analysis for sentences (1)-(2) as described above.
3. Parse. Your output should look exactly like the output decribed in the document Exercise-9-expected-output.pdf on Olat.

Note that the complementizers in (1) and (2) cannot be exchanged:

(3) *Fred asked that Lilly disappeared
(4) *Fred thought whether Lilly disappeared

The reason is that there is an incompatibility of clause type information in (3) and (4): the verb thought requires a declarative clause as its COMP, but the word whether can only head interrogative clauses. In (4), we find the opposite incompatibility.

Exercise 10

1. Open your current version of Grammar Grammar 9 - 2026-02-04
2. Add the feature CLAUSE_TYPE to the lexical entries that need it so that (3)-(4) are not accepted by the grammar for the reasons stated above, but (1)-(2) stay grammatical.
3. Parse. Your output should look exactly like the output decribed in the document Exercise-9-expected-output.pdf on Olat.

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