There was/were… there has/have been… there will be…

Let's break down the grammar rules and usage of 

"There was/were," 

"There has/have been,"

"There will be."

1. THERE WAS/WERE

   - "There was" is used in the singular form, and "there were" is used in the plural form.

   - This construction is used to indicate the existence or occurrence of something in the past.

   - The word "there" is known as an introductory pronoun and is followed by the verb "was" or "were."

Examples:

     - "There was a dog in the park." (singular)

     - "There were many books on the shelf." (plural)

2. THERE HAS/HAVE BEEN

   - "There has been" is used in the singular form, and "there have been" is used in the plural form.

   - This construction is used to talk about events or situations that started in the past and continue up to the present (Present Perfect).

   - The word "there" is followed by the verb "has" or "have" and then the past participle of the main verb.

Examples:

     - "There has been a change in the company's policy." (singular)

     - "There have been several meetings about the project." (plural)

3. THERE WILL BE

   - This construction is used to refer to future events or situations.

   - The word "there" is followed by the verb "will" and then the base form of the main verb.

Examples:

     - "There will be a party at my house next week."

     - "There will be heavy rain tomorrow."

Note: These constructions are typically used to introduce the subject of the sentence, and the main subject usually follows the verb phrase. For example:

- "There was a cat in the garden." (subject: a cat)

- "There have been some complaints about the noise." (subject: some complaints)

- "There will be many guests at the wedding." (subject: many guests)

Remember to adjust the verb forms according to the subject (singular or plural) and the tense (past, present, or future) you want to express.