Alternative b) Students and I talked about the importance of rigorous study and organization.
Correction: Students and I talked about the importance of rigorous study and organization. OR Students and I talked about the importance of rigorous study and organization.
Regarding verb agreement, when the compound subject is formed by different grammatical persons, the agreement must be made in the following order: 1st person, 2nd person and 3rd person.
In this case, the verb (to speak) should agree with the 1st person (I) and not with the 3rd person (they, in reference to the students).
As far as nominal agreement is concerned, as the adjective (strict) is after the nouns, it should have agreed with the closest noun (organization), in this case being "organization strict".
But, it could also have agreed with all the nouns (study and organization), in this case being "rigorous study and organization".
Alternative e) All alternatives are correct.
With regard to verb agreement, both "fled" and "fled" can agree with the compound subject (in this case, "teacher" and "students"). When the compound subject comes after the verb, the agreement can be done in two ways: in the singular, agreeing with the closest subject (in this case, "professor"), OR in the plural, agreeing with two subjects (in this case, "professor" and "students").
Regarding nominal agreement, both "year" and "years" can be used, because when ordinal numbers come before a noun (in this case, the seventh and eighth numerals are before the noun year), the noun may agree with the nearest numeral (eighth year) or with all of them (seventh and eighth years old).
Alternative a) Now, these are more serious cases, more difficult to resolve.
In this case, the pronoun "se" has the function of index of indeterminacy of the subject. In these cases, the verb must always be in the 3rd person singular (in this case, "treat").
As for the other alternatives:
b) There will be riots in the square.
Correction: There will be riots in the square. OR There will be riots in the square.
When the verb to have is indicating an event, as in this case, it is impersonal and, therefore, must be in the 3rd person singular. It is wrong to say "There will be riots in the square.", just as it is wrong to say "There will be riots in the square."
c) The causes of erosion on these lands are no longer discussed.
Correction: The causes of erosion on these lands are no longer discussed.
In this case, the pronoun "se" is a passive particle, indicating the action that the subject is undergoing (The causes of erosion of these lands are not discussed further). In this case, the verb "discuss" has to agree with the subject "causes".
d) In the absence of modern medicines, the wounds caused by the bush were treated with home remedies.
Correction: In the absence of modern medicines, the wounds caused by the weeds were treated with home remedies.
In this case, the pronoun "se" is a passive particle, indicating the action that the subject is suffering (The wounds caused by the bush were treated with home remedies). In this case, the verb "to treat" has to agree with the subject "injuries".
e) It must have been two years since they moved here.
Correction: It must have been two years since they moved here.
When the verb make is indicating tense, as in this case, it is impersonal and, therefore, must be in the 3rd person singular.
Correction:
Most friends did not agree (or agreed) with the idea. More than one wanted to explain the reason for the disagreement, but more than one disagreed. Several of us were (or were) quite upset and I was a little nervous.
Most friends agreed or agreed are right, because when the subject contains a partitive expression, such as “a mais parte”, followed by a plural noun (in this case, “amigos”) the agreement can be made in two ways:
the verb can be singular, agreeing with “most”, OR it can be plural, agreeing with “friends”.
more than one wanted is right, because when the subject contains an expression that indicates approximate quantity, the verb must agree with the numeral (in this case, “one”).
More than one disagreed is right, because in this case, the verb to disagree is expressing reciprocity.
Several of us were upset or stayed upsets are right, because when the subject is an indefinite pronoun, such as “various” and is accompanied by “we”, as in this case, the agreement can be done in two ways:
the verb can agree with the pronoun “various”, staying in the 3rd person plural (in this case, “stay”), OR it can agree with “nós” (in this case, “stay”).
quite upset that's right, because "quite" is an adverb of intensity, and adverbs are invariable.
kinda nervous is right, because "means" is an adverb of intensity, and adverbs are invariable.
Alternative c) They were the most elegant boys possible.
Correction: They were the most elegant boys possible.
The expressions "as much as possible, as little as possible" must agree with the accompanying article. Thus, "the most (elegant) possible".
The agreement of proper names depends on the presence of articles. Proper names WITHOUT article must be singular, while Proper names WITH article must be plural. So, these are the correct options for:
The) You U.S are a country made up of 50 states.
B) You lusíadas checked great value to Portuguese literature.
c) Amazon promotes one of the biggest folklore festivals in the country.
and) At Minas Gerais welcome your visitors well.
In the case of the name of works, such as Os Lusíadas, if the sentence is formed by the verb to be and a predicate that is in the singular, the name of the work can be in the singular. This is the case for:
g) Os Lusíadas is a fantastic work.
The expressions "it is necessary, it is allowed" do not vary, unless the nouns are accompanied by determiners, such as articles. So, these are the correct options for:
d) It is necessary calm.
f) THE wisdom is necessary.
H) It's allowed beach clothes.
Alternative b) The correct sentences are 1, 3, 4 and 5.
1) 1% do not approve of the decision.
The verb must agree with the percentage number when the percentage is not accompanied by a noun.
3) It was me and my colleague who sent the invitations.
The verb must agree with the pronoun that comes before the pronoun that (in this case, "my colleague sent")
4) We were the ones who sent the invitations.
The verb must agree with the pronoun that comes before the pronoun that (in this case, "we send")
5) I was the one who answered the call.
Agreement with the pronoun who can be done in two ways: by agreeing the verb with the pronoun that is before the who, as was done in this case ("eu answered") OR leaving the verb in the 3rd person singular (I was the one who answered the call.).
Correction of sentence number 2: 1% of respondents agree with canceling the party.
Agree is correct, because when the subject is a percentage, the verb must agree with the noun that accompanies it (in this case, "interviewed").
Alternative b) Forgive victim and relieved criminal.
As for verb agreement, since the verb "to forgive" has the idea of reciprocity and comes before the subjects "victim" and "criminal", it must be plural (in this case, "forgiven-se").
With regard to nominal agreement, the predicate of the compound subject that is after the subject, as in this case, must agree with both subjects (in this case, "victim and criminal relieved").
Although both sentences are correct, in sentence a) there is more emphasis on the lawyer, conveying the idea that the withdrawal comes from him.
In turn, sentence b) conveys the idea that giving up is a decision taken together.
Alternative c) we repair, will have.
Neither she nor I noticed. Now, I or she will have to correct the typing.
Neither I nor she noticed is right, because when the word is not even used to join a compound subject, the verb must be plural. In this case, she and I didn't notice the error.
I or she will have is right, because only one person will correct the mistake, so the verb has to agree in the singular.
Alternative a) It is already half past twelve; There are only a few minutes left for the meeting to begin.
As far as nominal agreement is concerned, "half" refers to thirty minutes, ie half an hour. Thus, the agreement must be made in the feminine.
With regard to verb agreement, the verb "faltar" must agree with the subject "few minutes". Thus, the agreement must be made in the plural.