Can I use XHTML technology only to build an EPUB 3.0 book? I want to build EPUB book with "The Three Little Pigs" story.

Yes, you can use XHTML technology only to build an EPUB 3.0 book.

For example, you can download this EPUB book, 3Pigs1-3.0.epub, which has the entire "The Three Little Pigs" story coded in a single XHTML file, content.xhtml:

<?xml version="1.0" encoding="utf-8"?>
<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <title>The Three Little Pigs</title>
  </head>
  <body>

<h2>The Three Little Pigs</h2>

<h4>The Opening</h4>

<p>Once upon a time there were three little pigs. One day their mother 
said, “You are old now. You can make your own houses.” Mrs. Pig kissed 
each little pig on the nose. “Take care! There is a big bad wolf about. 
Build your houses good and strong, and NEVER NEVER let that bad old wolf 
through the door.” The three little pigs said, “Bye, bye mom!” and off 
they went.
</p>

<h4>The First Pig</h4>

<p>The first little pig saw a farmer with some straw. So he said to the 
farmer, “Please give me some straw to build a house.” The farmer said, 
“Yes” and gave the little pig a big bundle of straw. The little pig said, 
“Thank you!” and he made a house of straw.    
</p>

...

If you open 3Pigs1-3.0.epub in Calibre, you see "The Three Little Pigs" story displayed nicely in a single reading flow:

⇒ 3Pigs2-3.0.epub - Multiple XHTML Files

⇐ EPUB 3.0 With XHTML Technologies

⇑ EPUB 3.0 With XHTML Technologies

⇑⇑ EPUB Tutorials