11.   A huge fire of unknown origin engulfed thousands of acres of trees, farms and fruit orchards near here.

12.   About nine years ago, Quinn developed idiopathic cardiomyopathy, a heart muscle disease with unknown origin.

13.   But there is still a lot of methyl chloride of unknown origin.

14.   He called in environmental experts from Rutgers University, who established that it was a peculiar but not harmful fungus of unknown origin.

15.   I did find several recipes, most of them of unknown origin.

16.   In July, an FDA advisory panel unanimously voted that the drug was safe and effective for treating patients with fevers of unknown origin.

17.   Instead, it was a failure of unknown origin in a well-developed technology that has been used successfully in the rockets that have launched satellites and missiles for decades.

18.   Israeli officials dismissed the document as speculative and Americans officials said it was unofficial, of unknown origin and inaccurate.

19.   Israeli officials dismissed the document as speculative, and U.S. officials said it was unofficial, of unknown origin and inaccurate.

20.   It was the first symptom of a very aggressive cancer of an unknown origin.