new safety system _______ to use, the accident would never have happened.

I don’t doubt _____ he took the first place in his class; but I do doubt _____ he will succeed in the end.[ ]

下列词语中，没有错别字的一组是(　　)

The _______ boy made the police and his family _______.

With the nuclear crisis worsening in Iran, the world’s attention is fixed again onis called the Middle East．