Question

как пришется правильно: Look! Mary is dance или dancing

Answer 1

Вообще, правильнее смотреть по тексту. Скорее всего dancing 

Answer 2

Correct Form: Look! Mary is dancing.

The correct form in this sentence is "dancing." The verb "is" is used with the present participle form of the verb, which ends in "-ing." Therefore, the correct sentence is "Look! Mary is dancing." In English, the present continuous tense is used to describe an action that is happening at the moment of speaking or around the current time. In this case, Mary is currently engaged in the activity of dancing.