问题
选择题
Some students are so ______ that they often make mistakes in their homework.
A．carful
B．serious
C．careless
D．successful
答案
答案：C
词义辨析。careful仔细的；serious严重的；careless 粗心的；successful成功的。根据句意：他们做作业经常犯错误，应该是粗心才会引起错误的。故选C。