The use of the past tense verb "were" indicates that the main verb of the sentence, "knows," should also be in the past tense, as they should be in agreement. Thus, the verb "knows" needs to be changed to its past-tense form. "No one knew where the paintings" is the only answer choice that correctly does this.

The subject of the sentence is actually the gerund phrase "Making up stories," which is a singular construction, despite the use of "stories." The verb, therefore, must match the singular subject, but is written in a plural form. "Making up stories is one of the chief ways" is the answer choice that best corrects this issue.

The answer choice "argue that a feeling of connectedness with other human beings, along with a positive self-image, contributes to the overall health" is correct. It contains the correct number agreement of the verb "contributes" with its subject, "a feeling of connectedness with other human beings."

The answer choices containing "contribute" instead of "contributes" are incorrect. The subject of "contribute" is singular, not plural.

Although the answer choice "argues that a feeling of connectedness with other human beings, along with a positive self-image, contributes to the overall health" correctly contains "contributes," the verb "argues" introduces a number agreement error, as "argues" is singular but being used with a plural subject, "Freud and other advocates of introspective psychology."

The use of "all" is the key indicator of the correct answer in the sentence. While "Tom, Dick, and Harry" are singular as individuals, they are "all" together sharing their feeling as a plural group; therefore, "all lament" is the correct choice among the answers.

The underlined portion does not show proper subject-verb agreement. Although there are "children" playing, the sentence refers to "each," which is singular. "Each of the children is" is the correct answer.

The original text contains a pronoun agreement error. The possessive pronoun "their" is plural, but it is intended to refer to the singular noun "individual." We must use singular possessive pronouns instead, such as "his or her."

Only answer choices "depends on his or her weight, height, and how old they are" and "depends on his or her weight, height, and age" correctly use "his or her" instead of "their," but answer choice "depends on his or her weight, height, and how old they are" does not use correct parallel structure. Therefore, the answer choice "depends on his or her weight, height, and age" is correct.

The original text contains a pronoun reference error. The antecedent of "its" is "empires," which is plural. We should therefore use the plural possessive pronoun "their" instead of the singular possessive pronoun "its." Only the answer choice "is that they became too large for their governments to collect tax revenues from citizens" correctly uses the plural posessive pronoun.

The original sentence lacks agreement. “Half of the states” is plural and in the third person, so it should say “as their official languages.” 

Since the government is a thing or institution, the sentence should say “its taxpayers.” The contraction “it’s” stands for “it is,” and therefore, is not possessive.

The pronoun "it" should be plural because its antecedent is the plural subject "resources." Only two choices correcty change "it" to "they," but one of them, "as they depend on the reduction of foreign oil," confuses cause and effect. The resources are not dependent on the reduction of foreign oil. The correct answer is "as they may reduce our dependence on foreign oil."