Not all Spanish galleons that are found to contain treasure. ??
The original sentence was "Not all Spanish galleons that are found contain terasure" T thought there were double verbs, "found" and "contain". So, I changed the sentence become

"Not all Spanish galleons that are found contain treasure"

Then I realized, that was not a double verbs, "found" is a part of preposition of "Not all Spanish galleons that are found" which is the Subject. So the sentence need a verb "contain", not "to contain", because "to contain" is to infinitive which is can be a Subject too.

Does my argument right?

Question

Not all Spanish galleons that are found to contain treasure. ??
The original sentence was "Not all Spanish galleons that are found contain terasure" T thought there were double verbs, "found" and "contain". So, I changed the sentence become

"Not all Spanish galleons that are found contain treasure"

Then I realized, that was not a double verbs, "found" is a part of preposition of "Not all Spanish galleons that are found" which is the Subject. So the sentence need a verb "contain", not "to contain", because "to contain" is to infinitive which is can be a Subject too.

Does my argument right?

Answer

Your analysis/argument is mostly correct.

I think what you're saying/asking is that there are two sentences that look similar, but say very different things:

- Not all Spanish galleons that are found contain treasure.
- Not all Spanish galleons are found to contain treasure.

These divide into [subject] [predicate] like so:

- [Not all Spanish galleons that are found]  [contain treasure]
- [Not all Spanish galleons]  [are found to contain treasure]

In the first case, "contain" agrees with "galleons". In the second case, "are found" agrees with "galleons".

Answer

Oops, the original sentence

Answer

I'm sorry Bill. Yes you're right. I should write the oroginal sentence to be

Not all Spanish galleons that are found to contain treasure

Answer

I think there is  a mistake in your question - the original sentence and the changed sentence look the same to me.  In any case, your analysis appears correct to me.  "that are found" describes the type of Spanish galleons. The verb is "contain".