问题补充：
Realizing that everything she said had no effect on her son, .
A. her son’s teacher was asked to help solve the problem.
B. it was decided that her son’s teacher should help solve the problem.
C. She had to ask her son’s teacher to help solve the problem
D. there’s nothing she can do but ask her son’s teacher to help solve the problem.
答案：
A. her son’s teacher was asked to help solve the problem.
B. it was decided that her son’s teacher should help solve the problem.
(答案→)C. She had to ask her son’s teacher to help solve the problem
D. there’s nothing she can do but ask her son’s teacher to help solve the problem.
解析：句意：意识到她说的任何话都对她的儿子没有效果，她不得不向她儿子的老师寻求帮助，来解决这个问题。前面用的现在分词作原因状语，所以“意识到”和其逻辑主语之间是主动关系，故逻辑主语应该是“She”，选C。
