| His true marvel has been to maintain an equable temper in conditions which really ought to have quadrupled his 15-a-day smoking habit. |
| Not only has spam quadrupled but the spammers' technology and methods also have been adopted by virus writers, grifters, and thieves. |
| Perth's population quadrupled in a decade, with many newcomers fleeing the depression in the eastern states. |
| Internet use in China has quadrupled since 2000 and ultimately censorship may prove futile. |
| More than a year later, North Korea may have quadrupled its arsenal of nuclear weapons. |
| The prices of some houses, especially in the downtown area, have tripled and even quadrupled. |
