Here are my two δραχμαί:
There are two clauses here. In the first clause, the syntactic subject is the singular ὁ λαός. In the second clause, the syntactic subject of ἐθαύμαζον is not expressed (zero anaphora), but its third-person plural ending implies a plural antecedent.Luke 1:21 wrote:καὶ ἦν ὁ λαὸς προσδοκῶν τὸν Ζαχαρίαν, καὶ ἐθαύμαζον ἐν τῷ χρονίζειν αὐτὸν ἐν τῷ ναῷ.
Though the subjects are syntactically different, the zero anaphora suggests a continuity of topic: both clauses are about the same group of people.
The antecedent for the plural implied subject of ἐθαύμαζον is the singular collective noun ὁ λαός. As already noted earlier in the thread, this is an instance of constructio ad sensum, which is not uncommon in Greek.
In this case, the construction is not particularly harsh because the singular antecedent is in a different clause than its zero-anaphora reference, but, as the earlier quoted BDF section indicates, there are harsher examples of constructio ad sensum, even in Luke.
Stephen