Hi, could you please tell me if these 2 sentences are correc.

Each of the twins has a doll in their room.
2. The couple have gone on vacation.

Also, when you have neither....nor, you use has don't you?

Example
Neither Helen nor Sarah has finished their homework.

Yes, you are right.

Both sentences are correct, and you're correct about using "neither...nor" too.

Thanks!

You're very welcome!

Sure, I can help you with that!

Regarding your first question, the correct verb agreement depends on whether the subject is singular or plural. Let's look at each sentence one by one:

1. "Each of the twins has a doll in their room."
In this sentence, "each" implies that we are talking about the individual twins separately. Since we are referring to each twin individually, the verb should be singular. So, the correct sentence would be: "Each of the twins has a doll in his or her room." Using "his or her" is more precise, but if you prefer a gender-neutral pronoun, you can use "their" instead of "his or her."

2. "The couple have gone on vacation."
In this sentence, "the couple" refers to two people as a unit. Since it's a single unit, the verb should be plural. So, the correct sentence is: "The couple has gone on vacation."

Now, moving on to your second question about using "has" with "neither...nor." When a subject is connected by "neither...nor," we match the verb with the closest subject. Let's analyze the example sentence:

"Neither Helen nor Sarah has finished their homework."
In this sentence, "neither Helen nor Sarah" creates a compound subject, but since "Sarah" is the closest to the verb, the verb should agree with it. Therefore, the correct sentence is: "Neither Helen nor Sarah has finished her homework."

To summarize, the corrected sentences are:
1. "Each of the twins has a doll in his or her room."
2. "The couple has gone on vacation."
3. "Neither Helen nor Sarah has finished her homework."

I hope this clarifies your questions!