A free relative clause in English is characterized by the following features:
| 1. | it is introduced by a wh-word (or a morphologically complex word which contains a wh-element); |
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| 2. | it can be substituted by a semantically equivalent DP or PP; and |
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| 3. | it contains a trace (it is therefore generated by movement). |
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Consider the following examples from English:
| 1. | a. | I tasted [what Adam cooked]. |
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| b. | I wonder [wh-INT what Adam cooked]. |
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| c. | I tasted [DP the thing(s) Adam cooked]. |
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| d. | *I wonder [DP the thing(s) Adam cooked]. |
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| (Caponigro 2003) |
The example in (1a) contains the free relative clause what …