Fill in the blanks with the correct option :
My friend lost his chemistry book. Now he doesn't know _____ to do and _____ to look for it.

Question

Accepted Answer

Option 1 is the correct choice for filling in the blanks in the sentence: "My friend lost his chemistry book. Now he doesn't know what to do and where to look for it."

1. **Explanation for Option 1:**
   - The word "what" is used to refer to a specific thing or action that needs to be identified or decided upon. In the context of the sentence, "what to do" implies that the friend is unsure about the actions he should take after losing the book.
   - The word "where" is used to refer to a place or location. "Where to look for it" indicates that the friend is uncertain about the location or places he should search to find the lost book.
   - Therefore, Option 1 correctly fills the blanks with "what" and "where," making the sentence logically coherent and contextually appropriate.

2. **Explanation for why other options are incorrect:**
   - **Option 2: where, what**
     - Using "where" in the first blank would imply that the friend is unsure about a location to do something, which does not fit the context of deciding an action. Similarly, "what" in the second blank would incorrectly suggest identifying an object or action to look for, rather than a location.
   - **Option 3: which, how**
     - "Which" is typically used to choose between a set of options, which is not applicable here as the friend is not choosing between specific actions. "How" refers to the manner or method of doing something, which does not fit the context of searching for a location.
   - **Option 4: how, when**
     - "How" in the first blank would imply a method or manner of doing something, which is not suitable for deciding an action. "When" refers to time, which is irrelevant to the context of searching for a location.

In conclusion, Option 1 is the only choice that logically and contextually fits the sentence, making it the correct answer.