1.   All ski instructors look like they do cologne commercials in the off-season, which doubtless explains the popularity of skiing among women.

2.   But Lewis and Clark need no best seller or television mini-series to explain their popularity.

3.   Cerf explained the popularity of such truncated endings.

4.   Explaining the popularity of these publications, Guccione puts it in terms that are more sociopolitical than sexual.

5.   Given all of these drawbacks and more, what explains the considerable popularity of leasing, which accounts for about one-third of all auto transactions?

6.   It must have been the ladle of flaming liquor that explains the popularity of American classic desserts such as Cherries Jubilee.

7.   The general expansion of the corporate counseling and referral services known as employee assistance programs may help explain the popularity of pastors in the workplace.

8.   This atmosphere explains the popularity of hallucinogenic drugs at raves.

9.   This fantasy world may explain the popularity of dollhouses that spans cultures and transcends time.

10.   Those factors also explain the popularity of fantasy sports leagues.