Build a Sentence: Why Wh- Words Don't Always Go to the Front: The "Know" vs. "Think" Rule

 

TOEFL Writing Build a  Sentence

Our big question today is this:
Should the Wh-word go at the beginning of the sentence, or in the middle?

Let’s look at two examples:

• How old do you think I am?

• Do you know how old I am?

Both sentences are correct. But these are incorrect:

• How old do you know I am? ❌
  Do you think how old I am? ❌

The sentence structure looks almost the same. The only difference is the verb: think vs. know.

So why does changing the verb force the Wh-word to move? 🤔

The reason is simple: these verbs ask different kinds of questions.

1️⃣ “Do you know…” → Yes/No Question

When we say:

Do you know how old I am?

We are asking whether you know or not.
The answer should be “yes” or “no.”

Because it’s a yes/no question, the sentence cannot start with a Wh-word.
Instead, it must start with an auxiliary verb like do.

The Wh-word is embedded inside the sentence as part of a noun clause.

Structure:

Do you know + [Wh-word] + [subject] + [verb]?

Examples of similar verbs include verbs of knowledge or fact, such as:

• know

• remember

• understand

• tell

• find out

These verbs introduce a noun clause, not a direct Wh-question.

2️⃣ “Do you think…” → Opinion Question

Now look at this sentence:

How old do you think I am?

Here, we are not asking yes or no.
We are asking for your opinion.

The answer might be:

• 25 years old

• 30 years old

• 100 years old! 😄

Since we are asking for the actual answer to the Wh-question, the Wh-word must come at the beginning.

Structure:

[Wh-word] + do you think + [subject] + [verb]?

Verbs that work like think include:

• believe

• suppose

• guess

These verbs ask for real answers, not just yes or no.

Summary: The verb determines where the Wh-word goes.

• Do you know how old I am? → Yes/No question

• How old do you think I am? → Real Wh-question
  
  

Practice questions

1.There is a stranger standing by the gate.
you / think / is / who / that / do / man / ?

2. We are completely lost and it’s starting to rain.
should / do / what / you / suppose / we / do

3. The tire tracks lead toward the woods.
way / which / think / they / do / went / you

4. This vintage car is beautiful, but it's in rough shape.
cost / how much / imagine / will / do / you / it

5. Sarah just ran out of the room covering her face.
is / why / do / think / you / crying / she

6. I need to return these books before the weekend.
know / where / do / you / is / the library

7. The boss looks very angry and is calling for a meeting.
tell / can / us / what / he / you / wants

8. The house was empty when I arrived at noon.
remember / you / do / they / left / when

9. ’ve been pressing every button, but nothing is happening.
explain / can / how / you / works / this

Answer Key

1. Who do you think that man is?
2. What do you suppose we should do?
3. Which way do you think they went?
4. How much do you imagine it will cost?
5. Why do you think she is crying?
6. Do you know where the library is?
7. Can you tell us what he wants?
8. Do you remember when they left?
9. Can you explain how this works?