In the first sentence, you need to add an -s to the verb (sings) because the subject (Merdine) is singular. They ombind the last -s of the verb (to sing) in the second sentence, because this is where the subject (sisters) is plural. However, remember that this rule only applies to verbs in the present tense. The verb “anger” is used with the theme “styles”, although the prepositional phrase “of the direction” and the adverb are “often” between the two words. Therefore, the verb must take a plural form to match the subject. “Stile. often angry” is the correct answer. Example: the list of items is on the desktop. If you know that the list is the subject, then select is for the verb. Over the past few years, the SAT test service has not judged any of you to be strictly singular.
According to merriam-Webster`s Dictionary of English Usage: “Obviously, since English, no singular and plural is and remains. The idea that it is only singular is a myth of unknown origin that seems to have emerged in the nineteenth century. If it appears to you as a singular in the context, use a singular; If it appears as a plural, use a plural. Both are acceptable beyond serious criticism. If none of them clearly means “not one,” a singular verb follows. . . .