问题
选择题
Knowing how long the test would last, the students who finished ____ back and waited until the end of the exam.
A．settle
B．settled
C．settling
D．to settle
答案
.B
该题考查句子结构。学生易犯思维定势的错误而选C，其实who finished是定语从句，该处缺谓语动词。