Which of the following best describes the main idea of the sentence: 'On another level, many in the medical community acknowledge that the assisted-suicide debate has been fueled in part by the despair of patients for whom modern medicine has prolonged the physical agony of dying'?

在NLP中，第一层次关注的是什么？

Select the appropriate word form: Her ______ about ancient history led to a groundbreaking discovery.

在正交变换下，二次型$f(x_1, x_2, x_3) = 2x_1^2 + 3x_2^2 + 4x_3^2 - 4x_1x_2 + 2x_1x_3 - 2x_2x_3$可以化为标准形$ay_1^2 + by_2^2 + cy_3^2$，其中$a, b, c$分别对应矩阵$A$的哪些特征值？

当评估潜意识构建的部分时，以下哪个方面是最需要注意的？