No. # 1 is a general statement about his hobbies and talents. # 2 doesn't make any sense with the use of "at once".
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
park sang joon1. He sings and dances.a) He sings, and he dances. (regularly, on various occasions)
park sang joon2. He sings at once and dances.Unusual, but
park sang joonDoes #2 mean "He sings and dacnes at the same time."?No. "at once" can sometimes mean simultaneously, but not in your sentence. Instead, "at once" seems to mean "straight away" (immediately after some other event mentioned), but the effect is unusual.
park sang joon3. He doesn't sing and dance.4. He doesn't do such a
park sang joonDoes #2 mean "He sings and dances at the same time."?No. For that you need He sings and dances at the same time.
park sang joon3. He doesn't sing and dance.a) He doesn't know how to sing and dance (at the same time).