I’ve gotten a number of questions about how to handle the do that shows up in a couple of the homework problems.

Here’s the deal. Check the textbook, p. 192, where you will find the Pronouncing Tense Rule. It says:

(160) Pronouncing Tense Rule (PTR)
In a chain (T[tense], v[uInfl:tense]), pronounce the tense features on v if v is the head of T’s sister.

Looking up a bit on the page, a chain is “an object which is formed by an Agree operation…when T checks tense features with little v, T and v are in a chain.”

This comes back in the discussion of Did Medea poison Jason? on pp. 341-2.

From the class handouts, look at handout #6a on pages 7-8. It’s also contained on handout #8a on pages 2-3. Handout #10a at the top of page 4 has an example of a yes-no question with did.

I think there actually isn’t an example of a wh-question with do on the handouts, but the principle is the same as in the situations I mentioned above.

Basically, the way we are thinking about this is as a pronunciation rule. So do isn’t actually in the tree. It’s rather like what we said about the of that represents of-case. If the conditions for the Pronouncing Tense Rule are met, then T is pronounced as an inflected do. That is, intuitively, if T winds up “far away” from the v (and T valued the [uInfl:] feature of v), then T gets pronounced as do and v is pronounced uninflected. T is “far away” when, e.g., T’s sister is NegP, or when T has moved to C. You don’t really need to write do anywhere in the tree, though if you do write it somewhere, it should presumably be basically as a pronunciation of T.