11.   Despite much research we cannot even today offer a convincing explanation.

12.   No convincing explanation was initially produced to explain these features.

13.   Also acceptable, but requiring a convincing explanation of what went wrong, are management blunders in corporations.

14.   And yes, there is as yet no convincing physiological explanation for the array of symptoms suffered by people with fibromyalgia.

15.   At least there has as yet been no convincing explanation.

16.   Absent so far in the debate has been a convincing explanation of why the immigration agency should stay within Justice, where it is a neglected stepchild.

17.   EMC needs a convincing explanation as to why profit margins, once astoundingly large, can be rebuilt to enviable if not comparable standards.

18.   Experts also cautioned that the lack of a convincing theoretical explanation makes the results somewhat suspect.

19.   The studies, however, have failed to come up with a convincing explanation of this calendar effect.

20.   They must be cash competitive and have a convincing explanation of why they want the office.