The three words: "when" , "while" and "whereas" often overlap and there is no sharp distinction.

Here is a Gap-fill exercise with these three words in question.

Fill in the blanks with either "when", "while" or "whereas", then press "Check" to check your answers.
1. Over half enjoy doing English homework, about one-third do not.

2. Guessing the word by looking at the context is a very useful way to learn the structure and phrases of the sentences and it allows me to think critically analyzing it.

3. English is an inflectional language Chinese is a non-inflectional language.

4. I learned English primarily through exposure to English communicating with my teammates and foreign customers.

5. Reading and listening are receptive, writing and speaking are productive.

6. As language users usually share assumptions and expectations communicating, it is common for them to convey various invisible meanings in the conversation.

7. Peter and songs are both assigned to the same class, in this particular clause they are serving different functions. Thus, they have different functional labels

8. Writing usually involves more careful planning compared with speech.

9. I showed students the recording conducting the interviews.

10. Americans use crosswalk, elevator, and truck, British people use zebra crossing, lift, and lorry.