This sentence contains an error in verb voice. The phrase "Conventions...are attended" is in the passive voice. The correct choice should always be in the active voice (i.e. the subject of the clause should be doing the action of the main verb). The correct choice is, "Millions attend conventions for anything imaginable."

This sentence contains an error in verb voice. The phrase "the technology was improved" is in the passive voice. The correct choice should always be in the active voice (i.e. the subject of the clause should always do the action of the main verb). This can be fixed by simply omitting the word "was." No other changes are necessary. The correct answer is, "Because the technology improved."

This sentence contains an error in verb voice. The phrase "Music was considered" is in the passive voice, which is totally unnecessary in this context. The correct answer will be in the active voice (i.e. the subject of the clause should always do the action of the main verb). The sentence needs to be reworded. The correct choice is, "She considered music extremely important." The other choices only add unnecessary words to the sentence. 

The phrase "the joke was laughed at" is in the passive voice. The correct choice should always be in the active voice (the subject of the clause should always do the action of the main verb). The sentence needs to be reworded. The correct choice is, "many laughed at the joke." The other choices are either still in the passive voice or are too wordy.

The phrase "The progress...was viewed" is in the passive voice. The correct choice should always be in the active voice (i.e. the subject of the clause should be doing the action of the main verb). The sentence needs to be reworded. All of the choices but one, however, are in the passive voice. The correct choice is, "They viewed the team's progress as insufficient."

This sentence contains an error in verb-voice. The phrase "The painting was found mesmerizing" is in the passive voice. The correct choice should always be in the active voice (i.e. the subject of the clause should always do the action of the main verb). The sentence needs to be reworded. The correct choice is "The painting amazed" as all the other options are still in the passive voice or a fragments.

This sentence contains an error in verb voice. The phrase "Experience is earned" is in the passive voice. The correct choice in this case should be in the active voice (i.e. the subject of the clause should always do the action of the main verb) because it is more concise and clear. The sentence needs to be reworded. The correct choice is, "You earn experience" as all the other choices contain fragments, passive voice, or subject-verb agreement errors.

Avoid the passive voice of the original ("it still needed alterations") and choose the simplest answer which preserves the meaning of the original sentence.

Note that the past perfect tense is used to refer to an action (A) which was initiated in the past and completed by the time of another action (B) also in the past. In this case the subject (B) "realized" that he (B) "had left his wallet at home". The other answer choices use active verb tenses such as the perfect progressive inappropriately and do not convey the meaning that is intended. 

This sentence contains no errors. "Around the world" is a prepositional phrase that is not separate from the rest of the sentence, so it is not necessary to offset it with commas. Additionally, commas are not used to separate an adjective from the noun it describes, so no comma should appear between "many" and "individuals." The correct choice is, "Many individuals around the world read."