Question

there is an _____ inside the pipe blocking the flow of water​

Answer 1

There is an obstacle inside the pipe blocking the flow of water

Explanation:

• In English, there were two articles and they are definite and indefinite articles.
• Definite article is used before specific nouns
• Definite article is "THE" and indefinite article is "A" an "AN
• Indefinite article is not only depends upon the spelling of the word but also depends upon the pronunciation of the word
• Mostly "an"  comes before the vowels of the English alphabet (a, e, i, o, u)
• Example - An apple, An orange, An ant, An umbrella, An elephant, An obstacle, An important,
• "An" comes before when a word starts with the letter "h", which is pronounced silently  
• Also, "An" is used before the indication of a member in group

There is an Obstacle inside the pipe blocking the flow of water

In the above sentence before the blank space there is "AN", undoubtedly the next word should start with a,e,i,o,u and "h"silent . The word Obstacle starts with vowel "O". Also, it can written as follows  

There is an Apple inside the pipe blocking the flow of water

To learn more...

1. https://brainly.in/question/4868392

2. https://brainly.in/question/11631114