Uso de Palabras Interrogativas WH con Infinitivos en Inglés

Understanding how to combine WH question words with infinitives is one of those grammar skills that makes your English sound significantly more natural and fluent. This structure appears constantly in everyday conversation, and mastering it will help you express uncertainty, make decisions, and describe situations with ease.

¿Qué son las WH question words seguidas de infinitivo?

Normally, we use who, what, where, when, and why to ask questions. However, these same words can also appear in statements when paired with the infinitive form of a verb [0:22]. The pattern is simple: question word + to + base verb.

Here are clear examples from the lesson:

• I never know who to trust when I buy a new car. [0:40]
• Jacqueline could never decide when to do her laundry. [0:58]
• We just have to determine where to go and what to do. [1:14]

Notice how the structure shifts from asking a question to making a declarative statement that expresses doubt, indecision, or a plan.

¿Cómo se practica esta estructura con don't know?

A very common and practical way to use this form is with the phrase "don't know" followed by the WH word + infinitive [1:30]. The lesson presents four useful examples:

• When does Mickey go to bed? → Mickey doesn't know when to go to bed. [1:48]
• Who should we send to get water? → I don't know who to send. [1:56]
• What should we name this dog? → I don't know what to name the dog. [2:02]
• Where should we put our shoes? → I don't know where to put our shoes. [2:07]

Each answer replaces the original question with a statement that communicates uncertainty or lack of knowledge. The question word stays, but the sentence structure changes completely.

¿Siempre va el infinitivo justo después de la question word?

Not always. There are cases where other words appear between the question word and the infinitive [2:18]. For example:

• I don't know what Jenny is going to do.

Here, the subject "Jenny" and the auxiliary "is going" separate what from to do. The infinitive appears at the end of the statement rather than immediately after the question word. The lesson recommends listening to native speakers to develop a natural sense of how these sentences are structured [2:35].

¿Cómo puedes practicar de forma efectiva?

The lesson suggests a speed round activity [2:45]: write 10 example sentences using different WH question words paired with infinitives. You can use tools like ChatGPT to check your grammar, share your sentences in the comment section for feedback, or download the worksheet from the additional materials for extra practice [2:55].

Here are some sentence starters to help you begin:

• I can't decide where to...
• She doesn't know what to...
• We need to figure out who to...
• He wasn't sure when to...

The more you write and hear these patterns, the faster they become second nature. Try creating your own 10 sentences and share them below!