Yes/no questions only get you yes or no. For real information — a place, a time, a price, a reason — you need wh-questions, the questions that start with words like what, where, when, who, why, which, whose, and how. "How much is this?" "When does the train leave?" "Why is the office closed?" Without them, you cannot ask for directions, prices, or explanations, and travel, shopping, and work all become guessing games.

There is also a special trap inside this topic. Sometimes the wh-word itself is the subject of the sentence, as in "Who called you?" These subject questions do not use do at all, and learners who add it ("Who did call you?") sound wrong. Knowing when to use do support and when to skip it makes your questions accurate, not just understandable.

A normal wh-question is built in three steps. Start with the wh-word, then put the auxiliary, then the subject, then the main verb. "Where + does + she + work?" "What + did + you + buy?" You can think of it as a yes/no question with a question word glued to the front: "Does she work here?" becomes "Where does she work?" The inversion rule you already know still applies.

As with yes/no questions, if the sentence has be or another helper, that word does the inverting and you never add do. "She is from Brazil" gives "Where is she from?" "You can meet at three" gives "When can you meet?" Only when there is no helper do you bring in do, does, or did: "He lives in Leeds" gives "Where does he live?" And after do/does/did, the main verb stays in its base form: "Where did he live?", never "Where did he lived?"

Now the special case: subject questions. Compare "Who did you call?" and "Who called you?" In the first, you did the calling and who is the object, so you need did. In the second, who is the person who did the action — who is the subject. When the wh-word is the subject, there is nothing to invert. Keep normal statement order and add no do: "Who called you?" "What happened next?" "Which bus goes downtown?"

Here is a simple test. Answer your own question with a short statement. If the answer puts the wh-word's information in the subject seat, it is a subject question. "Who called you?" — "Anna called me." Anna is the subject, so no do. "Who did you call?" — "I called Anna." Anna is the object, so do support is needed. In subject questions the verb usually takes -s in the present, because who and what act like he/she/it: "Who wants coffee?"

Finally, meet the how family. How joins other words to ask about amount and degree: how much (price, uncountable things), how many (countable things), how long (time), how often (frequency), how far (distance). These phrases sit in the wh-word position and the rest of the question is built the same way: "How often do you exercise?" "How far is the station?"

1. 1. What time does the store open?

   Wh-phrase first, then does, then the subject the store.

2. 2. Where did you park the car?

   Did builds the past question; park stays in base form.

3. 3. Why is the kitchen so cold?

   With be, just invert: is comes before the kitchen.

4. 4. When can we see the doctor?

   Can is a helper, so no do is added.

5. 5. How much does this jacket cost?

   How much asks about price; does supports the verb cost.

6. 6. How many people are coming tonight?

   How many counts people; are inverts with people.

7. 7. Who left this bag on the train?

   Who is the subject, so there is no did and no inversion.

8. 8. What happened at the meeting yesterday?

   What is the subject of happened; do support is impossible here.

9. 9. Which road goes to the beach?

   Which road is the subject, so goes keeps its -s.

10. 10. Whose phone is ringing right now?

    Whose asks about the owner; whose phone is the subject.

11. 11. How often do you visit your grandmother?

    How often asks about frequency and needs do support.

12. 12. Who did you invite to the party?

    Here who is the object, so did appears before you.

13. 13. Where were you at lunchtime?

    Past be inverts: were moves in front of you.

14. 14. How long did the flight take?

    How long measures time; take stays in base form after did.

The biggest mistake is dropping the auxiliary: "Where you live?" or "What she wants?" English needs the helper between the wh-word and the subject: "Where do you live?" "What does she want?" Without do, the sentence is missing a working part, like a bike without a chain — people may guess your meaning, but the question is broken.

The opposite mistake is adding do to a subject question: "Who did call you?" or "What did happen?" When who or what is the doer of the action, keep statement order: "Who called you?" "What happened?" Use the answer test: if the answer is "Anna called me," the question needs no do.

A third mistake is double tense after the helper: "Where did you went?" or "What does she wants?" The helper carries the tense alone, so the main verb goes back to its base form: "Where did you go?" "What does she want?" One tense per question — always.

• Build it as: wh-word + auxiliary + subject + base verb.
• Wh-word is the doer? No do: "Who called you?"
• Wh-word is the object or extra information? Use do: "Who did you call?"
• Check with the answer: subject answer means no do support.
• In subject questions, present verbs usually take -s: "Who wants tea?"
• Learn the how family as chunks: how much, how many, how long, how often, how far.