---Jack failed the driving test again. ---The question is_____ we can help him avoid making the same mistake.
The trick of the swindler(骗子) ______, the old man avoided being cheated.
Jimson found the map of great value when ______ Beijing.
His suggestion that a new teaching method ______ to arouse students’ interest in study is necessary.
Among so many scientists in this field, he ______ and achieved great success.
We all felt puzzled by the ______ answer he gave.