A detailed guideline on the usage and differentiation between When and While

In English, when we want to express events related to time, we often think of When and While. The questions arise: "When do we use 'When'?" and "When do we use 'While'?" or "What are the formulas for 'When' and 'While' in English?" PREP will answer all of these in this article. Let's refer to it right away!

I. What is When?

What is When? When is an English conjunction, used to create sentences about time, events, or conditions that have a connection between clauses. It is also used to indicate the time when an event, condition, or action happens after another event, condition, or action.

For example:

• When I go to the gym, I always do some cardio exercises. 
• When she arrived at the party, she greeted everyone with a smile. 
• When they have finished their homework, they can watch a movie. 

II. What is While?

What is While? While is an English conjunction used to create sentences about two actions happening simultaneously. While typically serves as a connector to combine two actions or events occurring at the same time. For example:

• While she is studying in her room, her brother is playing video games in the living room.
• I read a book while you were drying your hair.

III. The position of when and while in a sentence

In English, the position of When vs. While can vary depending on the context and the intended meaning you want to convey. Let's quickly explore the positions of When and While in English sentences. Take a look:

• The position of When in a sentence:
  • At the beginning of a sentence (to start the sentence), for example:  When I arrived at the station, the train had already left.
  • In the middle of a sentence (to indicate time, event, or condition), for example: I usually go for a run in the morning when the sun is rising.
• The position of while in a sentence:
  • Before the first clause (when one action interrupts another), for example: While I was doing my homework, my mother called me.
  • In the middle of a sentence (to indicate two actions happening simultaneously), for example: She is listening to music while her sister is reading a book.

IV. The usage of When and While in English

In addition to understanding the concepts of When and "While", it's important to know how these two words are used. Let's explore how to use When and While in each grammar structure below with PREP!

1. While

2. When

V. The difference between when and while

Let’s discover the similarities and differences between While and When in the below table provided by PREP!

VI. Exercises on when and while with detailed answers

To avoid confusion in the usage of When and While in English, it is important to not only study the theory but also practice through exercises. Below, PREP provides some questions for you to actively complete and check the answers below:

Exercise: Fill in the blank with when or while

1. _______ the bus arrives, we’ll get on.
2. I thought I heard him come in _______ we were having dinner.
3. _______ I reached the cinema, the movie had started.
4. I’m acting as deputy _______ the boss is away.
5. _______ the rain stopped, we went for a walk.
6. My mother is cooking _______ my father is preparing for the table.
7. _______ they ‘turned the TV on TV, the power went out.
8. Scarcely had he left the office _______ it started raining.
9. They arrived _______ he was working in the garden.
10. I was reading the newspaper while you were drying your hair.

Answer keys:

1. When
2. while/when
3. When 
4. while 
5. When 
6. while 
7. When 
8. when 
9. when/while
10. while 

VII. Smarter IELTS Preparation Starts Here

With the complete knowledge of When and While and the practice exercises provided here, PREP believes that you will no longer be confused when encountering these structures in your exams. If you want smarter ways to prepare, PREP’s innovative tools and strategies will transform your approach 

• IELTS preparation course: Turn Your IELTS Goals Into Reality