All flights    because of the storm, they had to wait in the hall.

    A．have put off                         B．were put off

    C．have been put off                                        D．having been put off

All flights _____because of the snowstorm，we decided to take the train instead.

A．were canceled                         B．had been canceled

C．having canceled                        D．having been canceled

All flights _____because of the snowstorm，we decided to take the train instead.

 All flights ____ because of the snowstorm, many passengers could do nothing but take the train.

A．had been canceled                      B．have been canceled

C．having been canceled                    D．being canceled

All flights___ because of the snowstorm, we decided to take the train.