I need your help in this.

[Happy Puppy]

Someone who is certified (English Teacher) should help me in this issue. Which one is better?

I'm 18 year old or I'm 18 years old?

[Dandelion]

Originally Posted by Happy Puppy

Someone who is certified (English Teacher) should help me in this issue. Which one is better?

I'm 18 year old or I'm 18 years old?

I'm eighteen years old. OK
I'm an eighteen-year-old student. OK

[Happy Puppy]

Thank you very much! Another sentence: This is a thousand dollars or These are a thousand dollars?

[Dandelion]

Originally Posted by Happy Puppy

Thank you very much! Another sentence: This is a thousand dollars or These are a thousand dollars?

You're welcome.

This is a thousand dollars.

Expressions of time, money, and distance usually require a singular verb.

Ten miles is a long way to walk.
Fifty cents is the price.
Eight hours of sleep is enough.

[Happy Puppy]

Thanks again! My answer was good then. Unfortunately I often confuse myself with WAY too much thinking and still didn't learn to trust my instincts.

[Dandelion]

You're welcome.

Say: I still haven't learned to trust my instincts.

[Happy Puppy]

Yep! I have to use present perfect instead of past simple as past simple indicates a particular, finished time in the past.

[Happy Puppy]

Hey people! I have returned with another question! I need the answer of someone certified.

How would you say it:

Heaven and Hell does exist.
Heaven and Hell does not exist.
The cat and the dog enjoys taking a walk.


OR

Heaven and Hell do exist.
Heaven and Hell do not exist.
The cat and the dog enjoy taking a walk.

Thanks for your help in advance! :D

[Casiopea]

Originally Posted by Happy Puppy

Hey people! I have returned with another question! I need the answer of someone certified.

First, if you have a new question, please open a new post. Second, most of the people who help out on this site are not certified English teachers, but that doesn't really matter because they are very good at answering questions like yours.

Welcome.

Heaven and Hell do exist.
Heaven and Hell do not exist.
The cat and the dog enjoy taking a walk.

Each underlined phrase functions as a plural subject, so the verb should also be plural, do and enjoy. Here's a trick: try replacing the subject with a plural subject pronoun, they:

They do exist.
They do not exist.
They enjoy taking a walk.