He was a good swimmer so he ________ swim to the river bank when the boat sank.

1. A.
   could
2. B.
   was able to
3. C.
   succeeded
4. D.
   might

He was a good swimmer, so he ______ swim to the river bank when the boat sank.

A. could                             B. might                      C. was able to              D. must

He was so good a swimmer that he ________ swim to the river bank when the boat sank.

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He was so good a swimmer that he ________ swim to the river bank when the boat sank.

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