Explain the concept of subject-verb agreement in complex-compound sentences.

Subject-verb agreement is a grammatical concept that refers to the agreement between the subject and the verb in a sentence. In complex-compound sentences, which are sentences that contain both dependent and independent clauses, subject-verb agreement becomes particularly important.

In a complex-compound sentence, the subject of the sentence may be found in either the independent clause or the dependent clause. The subject can be a single noun or pronoun, or it can be a compound subject consisting of multiple nouns or pronouns connected by coordinating conjunctions such as "and" or "or."

When the subject is singular, the verb that follows it must also be singular. Similarly, when the subject is plural, the verb must be plural as well. This ensures that the subject and the verb are in agreement in terms of number.

For example, consider the complex-compound sentence: "The cat that is sitting on the mat and the dog that is barking in the yard are causing a commotion." In this sentence, the subject is "the cat" and "the dog," which are both singular. Therefore, the verbs "is sitting" and "is barking" are also singular to maintain subject-verb agreement.

However, subject-verb agreement can become more complex when dealing with compound subjects. In cases where the compound subject is joined by a coordinating conjunction such as "and," the verb should be plural. For instance, in the sentence "John and Mary are going to the party," the compound subject "John and Mary" is plural, so the verb "are" is also plural.

On the other hand, when the compound subject is joined by a coordinating conjunction such as "or" or "nor," the verb should agree with the subject closest to it. For example, in the sentence "Neither the cat nor the dogs are allowed inside," the verb "are" agrees with the plural subject "dogs."

In summary, subject-verb agreement in complex-compound sentences requires ensuring that the subject and the verb agree in terms of number. This involves using a singular verb with a singular subject and a plural verb with a plural subject. Additionally, when dealing with compound subjects, the verb should be plural when joined by a coordinating conjunction like "and," and it should agree with the subject closest to it when joined by "or" or "nor."