Before revision: For example, space shuttle launch countdowns included 7 holds at T-27 hours, T-19 hours, T-11 hours, T-6 hours, T-3 hours, T-20 minutes, and T-9 URL
After revision: For example, space shuttle launch countdowns included 7 holds at T-27 hours, T-19 hours, T-11 hours, T-6 hours, T-3 hours, T-20 minutes, and T-9 minutes.