"two extensions" is a perfectly acceptable phrase to use in written English.
For example, "The deadline for the project has been extended twice, with two extensions already granted."
"There had already been two extensions," Kendall said.
In addition, we present two extensions to the framework.
After getting two extensions, they were told they had to pay their rent or go.
Ellman and Gretzky had been given two extensions to wrap up the purchase.
They did, and made her pay arrears on the two extensions before taking them out.
After two extensions, the deadline for upgrading the state's underground tanks now stands at Dec. 22.
Two extensions are allowed; additional extensions require permission from the Graduate School.
To circumvent these difficulties, this paper suggests two extensions with respect to conventional synthesis procedures.
But China, which owns all giant pandas in U.S. zoos, had granted him two extensions, and the answer was no.
Therefore, this paper presents two extensions of the RGA-MPC technique.
Moreover, we present two extensions to SSiPP: Labeled-SSiPP and SSiPP-FF.
