1.   And if the technology for attaching the hydrogen to a metal for storage were perfected, the infrastructure for distributing and retailing liquid hydrogen does not exist.

2.   But Boeing and Bell say tilt-rotor technology has been perfected after years of study and development, and that the Osprey is safe.

3.   Dilworth said he plans to focus on developing and perfecting the technology.

4.   For three years it laid low, perfecting the technology.

5.   Imaginative new approaches to controlling both kinds of pollution are likely to involve plans for trading emissions credits and perfecting new technologies.

6.   It would be politically and financially reckless to start building an anti-missile system before the technology is perfected.

7.   Mike Lowesche of Ray Fruit Co. in McAllen, Texas, worked on the innovative vacuum-pack technique for five years before perfecting the technology.

8.   Now the pressure is on to perfect the technology.

9.   On-line music services are sometimes made available before the technology is perfected.

10.   The aim is to perfect technology for a rocket that could reach orbit in a single stage, without discarding any parts.