This question has been raised:

“On #8 in parsing on the worksheet for chapter ten, the “τινες” has no accent.
We can’t figure out how we ought to parse it, since both of the identical words in the book have accents [one on the penult, one on the ultima.]"

The confusion has to do with the nature of enclitics, as they relate to the rules of accent.

The indefinite pronoun, (τις, τι) is enclitic (throws its accent back), like most forms of εἰμι (BBG 8.12).

Following the rules of accent, we have:

εὗρεν δὲ ἐκεῖ ἄνθρωπόν τινα ὀνόματι Αἰνέαν (“There he found a certain man named Aeneas” – Acts 9.33)

The accent of τινα goes back to ἄνθρωπον because the rules of accent allow it.

However the accent cannot be thrown back when there is no preceding word, i.e. if the enclitic word begins a sentence, as in the case of:

Τινῶν ἀνθρώπων αἱ ἁμαρτίαι (“Some men’s sins…” – 1 Timothy 5.24)

Since Τινῶν is the first word in the sentence, it cannot throw its accent back. But you know it is the indefinite rather than the interrogative pronoun because it is oxytone (accented on the ultima), not paroxytone (accented on the penult).

The normally enclitic word will also retain its accent when throwing it back would result in the preceding word having accents on 2 successive syllables.

So while the example for Acts 9.33 above has the accent going back, in this case it cannot because is would result in two successive accents, viz. δύό τινας (try saying that):

καὶ προσκαλεσάμενος δύο τινὰς τῶν μαθητῶν αὐτοῦ (“and calling two of his disciples…” Luke 7.19)

Greek is a euphonious language, and it should be obvious why two successive accents are unacceptable. Here again you know that τινὰς is the indefinite rather than the interrogative pronoun because it is oxytone (accented on the ultima), not paroxytone (accented on the penult).

For more detail you can read Smyth on Enclitics, which includes:

Enclitics (from ἐγκλίνω lean on, upon) are words attaching themselves closely to the preceding word, after which they are pronounced rapidly. Enclitics usually lose their accent. (emphasis mine).

and

A paroxytone receives no additional accent: a monosyllabic enclitic loses its accent (χώρᾱ τις, φίλος μου), a dissyllabic enclitic retains its accent (χώρᾱς τινός, φίλοι τινές) except when its final vowel is elided.