1. Do you quietly think so?

2. Do you really think so?
3. Do you easily think so?
4. Do you finally think so?

5. He solved the math problem very quietly.
6. He solved the math problem very really.
7. He solved the math problem very easily.
8. He solved the math problem very finally.
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Which ones are unacceptable?

6 and 8 are unacceptable. The others are good. If he solved the math problem, then he really solved it; there's no need to add "really", much less "very really". It's either real or it's not; no modifier is needed. The same goes for "finally".

I think #s 1, 3, and 4 are awkward. #2 is a rather common expression, but I've never read or heard the others.

I agree with Reed about #s 5-8.

To determine which expressions are acceptable, we need to consider the meaning and usage of the adverbs "quietly," "really," "easily," and "finally."

1. "Do you quietly think so?" - This sentence is grammatically acceptable but may sound a little odd in most contexts. "Quietly" typically describes physical actions or sounds rather than thoughts. However, if someone wants to imply that the thinking process is calm and contemplative, using "quietly" to describe thinking may be acceptable.

2. "Do you really think so?" - This sentence is grammatically correct and commonly used. "Really" is an adverb that emphasizes the speaker's doubt or surprise about the statement being made.

3. "Do you easily think so?" - This sentence is grammatically correct but may require further context to determine its meaning. "Easily" usually describes actions or processes that require little effort or difficulty, rather than thoughts. However, if the intention is to inquire about someone's ability to form opinions or thoughts effortlessly, this usage may make sense.

4. "Do you finally think so?" - This sentence is grammatically correct but also requires more context to determine its intended meaning. "Finally" usually indicates the resolution or culmination of something, such as the conclusion of a long thought process. Again, without additional context, it may sound unusual when referring to thinking.

5. "He solved the math problem very quietly." - This sentence is grammatically correct and makes sense. "Quietly" here describes the manner in which the math problem was solved, suggesting a calm and focused approach.

6. "He solved the math problem very really." - This sentence is grammatically incorrect. "Really" is not typically used to describe the manner in which a math problem is solved. It is better suited for emphasizing doubt or surprise, as mentioned earlier.

7. "He solved the math problem very easily." - This sentence is grammatically correct and commonly used. "Easily" describes the level of difficulty encountered during problem-solving, indicating that the math problem was not challenging for him.

8. "He solved the math problem very finally." - This sentence is grammatically incorrect. "Finally" does not usually describe the ease or difficulty of completing a task like solving a math problem. It indicates the culmination or conclusion, rather than the effort or manner of solving.

Therefore, sentences 2, 5, and 7 are acceptable, while sentences 1, 3, 4, 6, and 8 may require additional context or rephrasing for clarity.