Select the most appropriate option to fill in blank.
I would like to know _____ this machine works.
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. how.
Context: The sentence is expressing a wish to know in what way or by what method the machine works, so the correct word should indicate the manner or method.
Meaning of the words:
Whatever: means anything or everything, regardless of what.
That: used to introduce a clause, often to state a fact.
What: used to ask for information about something.
How: means in what way or by what method.
Correct word: How
Reason: The sentence is not a question but a statement expressing a wish to know the manner of working. “How” correctly introduces the clause showing the method.
Final Sentence: I would like to know how this machine works.
Hence, the chosen option is correct.