I was surprised that no one（ ）them of the danger.
A、
warns
B、
warned
C、
has warned
D、
had warned
【正确答案】：D
【题目解析】：
根据前面的was surprised，说明空格处的事件为过去的时间，不选AC，因为警告在惊讶之前，我只能对发生过的事情惊讶，用过去完成时，had done，选D。句意：我很惊讶没有人警告他们有危险。
I was surprised that no one（ ）them of the danger.
I was surprised that no one（ ）them of the danger.
warns
warned
has warned
had warned
根据前面的was surprised，说明空格处的事件为过去的时间，不选AC，因为警告在惊讶之前，我只能对发生过的事情惊讶，用过去完成时，had done，选D。句意：我很惊讶没有人警告他们有危险。