1. He stood silent.

2. He remained quiet.
3. He lay speechless.
4. He stood silently.
5. He stood quietly.
6. He was standing arrogantly.
7. He was standing silent.

(Are they all grammatical? From #1 to #3, adjectives are used. In the other sentences, adverbs are used.)

Yes, they are all correct.

In the sentences with adjectives, the verb acts as a state of being verb. The adverbs follow action verbs.

Yes, all seven sentences are grammatically correct. However, there is a minor difference in the use of adjectives and adverbs in these sentences.

1. "He stood silent." - This sentence uses the adjective "silent" to describe the subject "he." It means he stood in a silent manner.

2. "He remained quiet." - Here, the adjective "quiet" describes the subject "he." It means he stayed or remained in a state of quietness.

3. "He lay speechless." - This sentence also uses the adjective "speechless" to describe the subject "he." It means he reclined or lay in a state of being unable to speak.

4. "He stood silently." - In this sentence, the adverb "silently" modifies the verb "stood." It describes how he stood, in a quiet or noiseless manner.

5. "He stood quietly." - The adverb "quietly" modifies the verb "stood," indicating that he stood without making much noise or disturbance.

6. "He was standing arrogantly." - Here, the adverb "arrogantly" describes how he was standing, suggesting that he displayed an air of superiority or self-importance.

7. "He was standing silent." - This sentence uses the adjective "silent" to describe how he was standing. It means he was in a state of silence while standing.

Yes, all of the sentences you provided are grammatically correct. In sentences 1 to 3, adjectives are used to describe the subject "He." Adjectives modify nouns or pronouns and provide more information about their qualities or attributes. In this case, the adjectives "silent," "quiet," and "speechless" describe how the person is not making any sound or speaking.

In sentences 4 to 7, adverbs are used to modify the verb "stood" or "was standing." Adverbs describe how an action is performed and usually end in "-ly," such as "silently," "quietly," and "arrogantly." In these sentences, the adverbs provide information on how the person was standing - for example, without making any noise, calmly, or with arrogance.

Both adjectives and adverbs can be used to provide more detail and enhance the meaning of a sentence. Therefore, all of the sentences are grammatically correct, but they differ in the specific parts of speech used.