Answer:
The statement is false because Isabel and Thami were not practicing for a choir competition at the beginning of the act. This could be due to several reasons:
1. **Textual Evidence**: There might be no mention or indication within the act that Isabel and Thami were practicing for a choir competition.
2. **Character Context**: If the characters' actions or dialogue at the beginning of the act do not suggest they were preparing for a choir competition, then the statement is false based on the context of the characters.
3. **Plot Development**: The act might focus on different events or themes that are unrelated to a choir competition. If the act unfolds in a way that doesn't align with choir practice or competition preparation, then the statement is false in the context of the plot.
Therefore, without any supporting evidence or context indicating otherwise, the statement is false.