Three different kinds of information
The question words When, Why, and How begin open questions: in the answer, the other person gives information, not just yes or no.
When means “at what time?” and asks you to name a time, day, or another moment. Why means “for what reason?” and asks you to explain a reason. How means “in what way?” and asks you to describe a method, manner, or state.
First, imagine a natural answer. At seven suggests When, Because I am tired suggests Why, and By bus suggests How.
When → time; Why → reason; How → method, manner or state
When does the lesson start?
When does the lesson start?
We expect an answer about time, for example At nine.
Why is Lena at home?
Why is Lena at home?
We expect a reason, for example Because she is ill.
How do you get to work?
How do you get to work?
We expect a method, for example By bus or On foot.
How to choose the right word
One situation may allow different grammatical questions, but they ask for different information. When does the train leave? asks for the departure time. Why does the train stop here? asks for the reason for the stop. How does the train cross the river? asks for a description of the method.
A grammatical question with a different question word is not always wrong. It may simply fail to achieve the intended communicative goal. Therefore, in an exercise, always check exactly what information you need to find out.
The answer because usually explains a reason after Why. Answers to When and How can take many natural forms, so the meaning matters, not just one word.
Needed information → appropriate question word
When do you study English? — In the evening.
When do you study English? — In the evening.
In the evening names a time, so the question begins with When.
Why do you study English? — Because I need it for work.
Why do you study English? — Because I need it for work.
Because introduces a reason, so Why is appropriate.
How do you study English? — With short videos.
How do you study English? — With short videos.
The answer describes a method, so How is appropriate.
Questions with a main verb
In the Present Simple, with main verbs such as work, start, travel, and cook, we put do or does before the subject. After do/does, the verb has its base form without -s.
With I, you, we, and they, we use do. With he, she, it, or one name, we use does. The -s ending moves from the main verb to does: Mia travels becomes How does Mia travel?
The complete order is: question word + do/does + subject + base form of the verb + the rest of the question.
When/Why/How + do/does + subject + base verb + ...?
- subject / S —
- The grammatical subject: who or what the clause is about; the verb agrees with it. In The book was written, the book is the subject, although someone else does the action.
- verb / V —
- A word for an action or state, such as work or be. The pattern determines its form.
- V1 / base form —
- The base verb without to: work, go, be.
When do you finish work?
When do you finish work?
The subject you goes with do, and finish stays in the base form.
Why does Amir walk to work?
Why does Amir walk to work?
The subject Amir requires does; after it, we use walk, not walks.
How does this machine work?
How does this machine work?
Does comes before the subject this machine, and work has its base form.
Questions with be
When the main verb is am, is, or are, we do not add do/does. We move the form of be before the subject.
The order is: question word + am/is/are + subject + the rest of the question. We use this to ask about the time of an event, the reason for a state, or someone’s condition.
How are you? is a common question about a person’s condition. Here, How does not ask you to describe transportation or a technical method.
When/Why/How + am/is/are + subject + ...?
- subject / S —
- The grammatical subject: who or what the clause is about; the verb agrees with it. In The book was written, the book is the subject, although someone else does the action.
When is the meeting?
When is the meeting?
Is is already the main verb, so does is not needed.
Why are the windows open?
Why are the windows open?
We put are before the subject the windows.
How is your new job?
How is your new job?
How asks for an evaluation of the condition or impression, and is comes before the subject.
Questions with can
If a sentence contains the modal can, it comes before the subject. We do not use do/does together with can.
After can, we always use the base form of the verb. The order is: question word + can + subject + verb.
This pattern is useful when we ask about a possible time, the reason something is possible, or the method of carrying out an action.
When/Why/How + can + subject + base verb + ...?
- subject / S —
- The grammatical subject: who or what the clause is about; the verb agrees with it. In The book was written, the book is the subject, although someone else does the action.
- verb / V —
- A word for an action or state, such as work or be. The pattern determines its form.
- V1 / base form —
- The base verb without to: work, go, be.
When can we meet?
When can we meet?
Can moves before we; we do not add another can or do.
Why can Mia leave early?
Why can Mia leave early?
Why asks for a reason, and can comes before the subject Mia.
How can I help?
How can I help?
How asks you to name a way of helping; help stays in the base form.
A question and an appropriate answer
A good question must not only have the correct word order but also fit the situation. To find out how someone travels to work, ask How do you get to work? To find out the arrival time, ask When do you get to work? If the answer has already been given, ask about what is still unknown.
We often answer Why with a sentence containing because, but shorter natural reasons are also possible: I’m tired or The bus is late. We can answer When with at eight, on Monday, or after work. We can answer How with by bike, on foot, or a complete description.
In a short dialogue, it is not necessary to repeat every word from the previous line. It is important to keep the participant, the action, and the required type of information.
I work in the evening. — When do you start?
I work in the evening. — When do you start?
The evening has already been named, but the exact starting time is still unknown. The short question asks for that detail; work is understood from the context.
I'm at home today. — Why are you at home?
I'm at home today. — Why are you at home?
The location is already known, but the reason has not yet been given. Why asks you to explain it.
I usually walk. — How do you get there in winter?
I usually walk. — How do you get there in winter?
How opens a follow-up question about the method in a new situation.
Limits of the rule and applying it in speech
This material practises direct questions with When, Why, and simple How. Constructions such as How old, How much, How many, and other combinations of How with an adjective or quantity belong to related rules.
When can also mean “when” inside a statement, and Why and How can introduce indirect questions. The word order there is different, but we do not practise those constructions here.
To apply the skill in speech, first identify the purpose: time, reason, or method. Then look at the verb: with a main verb, use do/does; with be, use inversion; with can, put the modal verb before the subject.
Purpose → When/Why/How; verb → do/does, be, or can
- verb / V —
- A word for an action or state, such as work or be. The pattern determines its form.
When do your classes finish?
When do your classes finish?
The purpose is time; finish is a main verb, so we use do.
Why is this bus empty?
Why is this bus empty?
The purpose is a reason; is is the main verb and moves before the subject.
How can we open the door?
How can we open the door?
The purpose is a method; can comes before the subject, and open stays in the base form.
Common mistakes
Incorrect:When you start work?
Correct:When do you start work?
In a direct Present Simple question with the main verb start, do is needed before the subject.
Incorrect:Why she is tired?
Correct:Why is she tired?
In a direct question, the form of be comes before the subject.
Incorrect:How does Leo gets to school?
Correct:How does Leo get to school?
After does, we use the base form get without -s.
Incorrect:When can we can meet?
Correct:When can we meet?
We put can before the subject only once; after it, we need the base form meet.
Incorrect:How you go to work?
Correct:How do you go to work?
With the main verb go and the subject you in the Present Simple, do is needed.