fixed typos (#29352)

* fixed typos

* fixed typos 

guide/english/design-patterns/object-oriented-programming/index.md

* fix typos

* fix typo css preprocessor index.md

guide/english/css/before-selector/index.md

@@ -3,7 +3,7 @@ title: Before Selector
 ---
 ## Before Selector
 
-The CSS **::before** selector can be used to insert anything before the content an element or elements. It allows the designer perform any css design before the content in an element. It is used by attaching **::before** to an element it is to be used on. 
+The CSS **::before** selector can be used to insert anything before the content an element or elements. It allows the designer to perform any css design before the content in an element. It is used by attaching **::before** to the element it is to be used on. 
 
 Let's look at some examples:
 
@@ -56,7 +56,7 @@ This will show `Hello world!!` in the page.
 Not only strings, also images, counters or even nothing ("", useful for clearfix) can be inserted into the `content` attribute, but <strong>not HTML</strong>. There are a good number of cool things that can be made using ```::before``` and ```after``` in a creative way. You can take a look in the next link if you are curious: <a href='https://www.w3schools.com/css/css_pseudo_elements.asp' target='_blank' rel='nofollow'>A Whole Bunch of Amazing Stuff Pseudo Elements Can Do</a>
 
 #### Single-colon vs. Double-colon
-There's a bit of discussion about the right way of using pseudo-elements: old style single-colon (```:before```), used in CSS specifications 1 and 2, versus CSS3 recomendation, double-colon (```::before```), mainly to <em>"establish a discrimination between pseudo-classes and pseudo-elements"</em>. But for compatibility reasons, single-colon is still accepted. Talking about compatibility, IE8 supports the single-colon notation only. 
+There's a bit of discussion about the right way of using pseudo-elements: old style single-colon (```:before```), used in CSS specifications 1 and 2, versus CSS3 recommendation, double-colon (```::before```), mainly to <em>"establish a discrimination between pseudo-classes and pseudo-elements"</em>. But for compatibility reasons, single-colon is still accepted. Talking about compatibility, IE8 supports the single-colon notation only. 
 
 #### More Information:
 

guide/english/css/css-preprocessors/index.md

@@ -46,7 +46,7 @@ Yet another feature which CSS lacks are If/Else statements. These will run a set
 Here, the background color will change color depending on the width of the page's body. 
 
 
-These are but a few of the major functions of CSS Preprocessors. As you can see, CSS Preprocessors are incredibly useful and versitile tools. Many web developers use them, and it is highly recommended to learn at least one of them. 
+These are but a few of the major functions of CSS Preprocessors. As you can see, CSS Preprocessors are incredibly useful and versatile tools. Many web developers use them, and it is highly recommended to learn at least one of them. 
 #### More Information:
 <!-- Please add any articles you think might be helpful to read before writing the article -->
 SASS: http://sass-lang.com/

guide/english/design-patterns/object-oriented-programming/index.md

@@ -12,7 +12,7 @@ In this paradigm, entities are represented as real world data. For instance, we
 
 ## OO concepts
 What makes OO programming powerful is its ability to do the following:
-* Inheritence
+* Inheritance
 * Polymorphism
 * Encapsulation
 * Abstraction
@@ -25,7 +25,7 @@ Another extremely useful concept is that of inheritance. The idea is that a clas
 
 This helps in reusing code and making your code structure much more clean. Data hiding is another cool feature. In OO, we have the notion of private and public attributes. Private attributes can be accessed and modified only by methods of that particular class, while public data can be modified from anywhere in the program (within scope obviously).
 
-OO programming represents problem as a real-life statement and thus helps us solve those problems in an effective way. An object in OO programming represents a real-life entity. A class represents a blueprint of a number of objects. An object can be considered as a instance of a class.
+OO programming represents problem as a real-life statement and thus helps us solve those problems in an effective way. An object in OO programming represents a real-life entity. A class represents a blueprint of a number of objects. An object can be considered as an instance of a class.
 
 ### Example:
 See the image below. It represents a blueprint of a class named car. An instance of this class can be a real-life car that performs functionalities such as getFuel(), setSpeed(), drive(), etc.