Try to analyze the four Fs. Were they all in one subject? Did your daughter have a bad week? Did something happen at home? Has she just started having trouble at school, or has she had problems since the start of the school year?
Have you asked the teachers why they think your daughter is not completing her work in class? Do they feel that the work is too hard for her? Do they think that she is being too sociable in the classroom or not using her time appropriately? You need the teachers' input to help get your daughter back on track.
Sometimes, students at this level are overwhelmed by having so many different teachers. We like the idea of your daughter talking individually with several of her teachers to find out how she can do better in their classes. Just getting to know them better and learning that they care about her efforts should be a step in the right direction.
Second, your daughter will benefit from learning some time-management, study, and organizational skills. Ask the school counselor about classes at the school, a local college, or a learning center that might help her learn these skills.
Finally, you should try to determine why your child now has so much attitude. Is it related to new friends, her struggle at school, or the onset of puberty? Grounding will not improve her attitude; however, helping her handle school, friends, and adolescence will.