Question

Samantha, in addition to Carrie, Charlotte, and Miranda, (is, are) going to the beach on Saturday.

Short answer

The correct sentence would be: 'Samantha, in addition to Carrie, Charlotte, and Miranda, is going to the beach on Saturday.'

Step-by-step solution

Identify the Subject

First, find out the subject of your sentence. In this case, the subject is 'Samantha'. Although there are other people mentioned, the sentence is specifically talking about Samantha.

Understand the Verb Agreement

The rule of thumb in English grammar is that a singular subject follows with a singular verb and a plural subject follows with a plural verb. Here, 'Samantha' is a singular subject.

Choose the Correct Form of Verb

Now that the subject is defined as singular (Samantha), the verb should be singular as well. The verb 'to be' in the present for a singular subject is 'is'.