Would like to clarify about the role of some words

Hi,

I found the following sentences in my grammar text book. I was asked to identify the verbs(helping,main) and the subjects related to the verb.

1. The economy of Venice is based on tourism; along with beautiful architecture and canals,there are numerous film festivals and events round the year that attract tourists.

My answers:
a. based(main); is(helping) -> The economy of Venice(subject)
b. are(main) -> there(grammatical subject); numerous film festivals and events round the year -> real subject)
c. attract(main) -> that(grammatical subject); numerous film festivals and events round the year -> real subject)

Among these (c) was not listed in the answer key. Am I wrong?

2. The British economy in early 30s, with an unemployment rate close to 20%, did not behave the way the classical economists had predicted, necessitating a new type of economic theory.

My answers:
a) behave(main), did(helping) -> The British economy in early 30s

In this sentence is "the way the classical economists had predicted" acting as adverbial phrase? Also what is the role of "necessitating a new type of economic theory." It implies a natural consequence. I am also wondering why we should not treat "had predicted" and "necessitating" as verbs.

Thanks,
Richards.