Over the past decades, sea ice _______ in the Arctic as a result of global warming.

1. A.
   had decreased
2. B.
   decreased
3. C.
   has been decreasing
4. D.
   is decreasing

Over the past decades, sea ice _______ in the Arctic as a result of global warming.

A. had decreased     B. decreased    C. has been decreasing     D. is decreasing

Over the past decades, sea ice _____ in the Arctic as a result of global warming.

A. had decreased    B. more than            C. attach               D. apply

Over the past decades , sea ice          in the Arctic as a result of global warming .

A. had decreased    B. decreased    C. has been decreasing    D. is decreasing  .

Over the past decades, sea ice     in the Arctic as a result of global warming.

A. had decreased  B. decreased   C. has been decreasing D. is decreasing