One day Chuck is on a flight across the Pacific Ocean _____ suddenly his plane crashes．

A．while          B．when          C．since         D．after

One day Chuck is ________ a flight ________ the Pacific Ocean ________ suddenly his plane crashes.

1. A.
   in; over; while
2. B.
   on; across; when
3. C.
   with; through; then
4. D.
   on; across; as

One day Chuck is ________ a flight ________ the Pacific Ocean ________ suddenly his plane crashes.

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