Update README.md

lessons/1-Intro/README.md

@@ -18,7 +18,7 @@ Originally, computers were invented by [Charles Babbage](https://en.wikipedia.or
 
 ---
 
-There are some tasks, however, that we do not explicitly know how to solve. Consider determining the age of a person from his/her photograph. We somehow learn to do it, because we have seen many examples of people of different age, but we cannot explicitly explain how we do it, nor can we program the computer to do it. This is exactly the kind of task that are of interest to **Artificial Intelligence** (AI for short).
+There are some tasks, however, that we do not explicitly know how to solve. Consider determining the age of a person from his/her photograph. We somehow learn to do it, because we have seen many examples of people of different ages, but we cannot explicitly explain how we do it, nor can we program the computer to do it. This is exactly the kind of task that is of interest to **Artificial Intelligence** (AI for short).
 
 ✅ Think of some tasks that you could offload to a computer that would benefit from AI. Consider the fields of finance, medicine, and the arts - how are these fields benefiting today from AI?
 
@@ -66,7 +66,7 @@ A top-down approach models the way a person reasons to solve a problem. It invol
 
 There are also some other possible approaches to intelligence:
 
-* An **Emergent**, **Synergetic** or **multi-agent approach** are based on the fact that complex intelligent behaviour can be obtained by an interaction of a large number of simple agents. According to [evolutionary cybernetics](https://en.wikipedia.org/wiki/Global_brain#Evolutionary_cybernetics), intelligence can *emerge* from more simple, reactive behaviour in the process of *metasystem transition*.
+* An **Emergent**, **Synergetic** or **multi-agent approach** is based on the fact that complex intelligent behaviour can be obtained by an interaction of a large number of simple agents. According to [evolutionary cybernetics](https://en.wikipedia.org/wiki/Global_brain#Evolutionary_cybernetics), intelligence can *emerge* from more simple, reactive behaviour in the process of *metasystem transition*.
 
 * An **Evolutionary approach**, or **genetic algorithm** is an optimization process based on the principles of evolution.
 

lessons/2-Symbolic/README.md

@@ -58,7 +58,7 @@ Untyped-Language | doesn't have | type definitions
 
 > ✅ Think how triplets can be used to represent other types of knowledge.
 
-2. **Hierarchical representations** emphasize the fact that we often create a hierarchy of objects inside our head. For example, we know that canary is a bird, and all birds have wings. We also have some idea about what colour a canary usually is, and what is their flight speed.
+2. **Hierarchical representations** emphasize the fact that we often create a hierarchy of objects inside our head. For example, we know that a canary is a bird, and all birds have wings. We also have some idea about what colour a canary usually is, and what their flight speed is.
 
    - **Frame representation** is based on representing each object or class of objects as a **frame** which contains **slots**. Slots have possible default values, value restrictions, or stored procedures that can be called to obtain the value of a slot. All frames form a hierarchy similar to an object hierarchy in object-oriented programming languages.
    - **Scenarios** are special kind of frames that represent complex situations that can unfold in time.
@@ -74,12 +74,12 @@ Program Length | | | 5-5000 lines |
 Block Syntax | Indent | | |
 
 3. **Procedural representations** are based on representing knowledge by a list of actions that can be executed when a certain condition occurs.
-   - Production rules are if-then statements that allow us to draw conclusions. For example, a doctor can have a rule saying that **IF** a patient has high fever **OR** high level of C-reactive protein in blood test **THEN** he has an inflammation. Once we encounter one of the conditions, we can make a conclusion about inflammation, and then use it in further reasoning.
+   - Production rules are if-then statements that allow us to draw conclusions. For example, a doctor can have a rule saying that **IF** a patient has a high fever **OR** a high level of C-reactive protein in a blood test **THEN** he has an inflammation. Once we encounter one of the conditions, we can make a conclusion about inflammation, and then use it in further reasoning.
    - Algorithms can be considered another form of procedural representation, although they are almost never used directly in knowledge-based systems.
 
 4. **Logic** was originally proposed by Aristotle as a way to represent universal human knowledge.
    - Predicate Logic as a mathematical theory is too rich to be computable, therefore some subset of it is normally used, such as Horn clauses used in Prolog.
-   - Descriptive Logic is a family of logical systems used to represent and reason about hierarchies of objects distributed knowledge representations such as *semantic web*.
+   - Descriptive Logic is a family of logical systems used to represent and reason about hierarchies of objects distributed knowledge representations such as the *semantic web*.
 
 ## Expert Systems