Many people in China have never dreamed of ______ a chance for them to learn to drive after their retirement

________ the calculation is right, scientists can never be sure that they have included all variables and modeled them accurately

_________not to miss the flight at 15:20, the manager set out for the airport in a hurry[ ]

All through history, big changes have taken place in ________ English language, especially when Henry IV became ________ King of England.

The air in Taizhou is getting ________ cleaner now than a few years ago.