1. She played the piano, singing a song.

1-2. She played the piano and sang a song.

2. Jenny is in the coffee shop, drinking coffee.
2-2. Jenny is in the coffee shop and drinking coffee.

3. Mike is standing there, listening to music.
3-2. Mike is standing there and listening to music.
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Are they all grammatical?
Is each pair the same in meaning?

1 and 3 seem to be grammatically correct, but with 2, the second sentence, "Jenny is in the coffee shop and drinking coffee." doesn't seem to be correct.

2. Jenny is in the coffee shop, drinking coffee.

2-2. Jenny is in the coffee shop and drinking coffee.
2-3. Jenny is in the coffee shop and is drinking coffee.
2-4. Jenny is in the coffee shop and she is drinking coffee.
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What about the sentences? Are they all grammatical and in simultaneous situation?

1, 2, 3, and all their variations are fine.

The ones with the extra words add variety, I guess, but the extra words aren't needed.

1. She played the piano, singing a song.

1-2. She played the piano and sang a song.

Both sentences are grammatically correct, but they have slightly different meanings.

In the first sentence, "She played the piano, singing a song," it implies that she was playing the piano while simultaneously singing a song. This suggests that she was multitasking, performing both actions at the same time.

In the second sentence, "She played the piano and sang a song," it indicates that she played the piano first and then sang a song separately. This implies that she performed the two actions consecutively rather than simultaneously.

2. Jenny is in the coffee shop, drinking coffee.
2-2. Jenny is in the coffee shop and drinking coffee.

Both sentences are grammatically correct and convey the same meaning.

In both cases, it means that Jenny is currently at the coffee shop and is actively engaged in the action of drinking coffee. The use of the conjunction "and" in the second sentence suggests that both activities are happening simultaneously.

3. Mike is standing there, listening to music.
3-2. Mike is standing there and listening to music.

Both sentences are grammatically correct and convey the same meaning.

In both cases, it means that Mike is currently in a standing position and is actively engaged in the action of listening to music. The use of the conjunction "and" in the second sentence suggests that both activities are happening simultaneously.