11.   Its scientists regularly test whether pesticide residue and other harmful agents are present in unhealthy amounts.

12.   NASA scientists are indeed testing inflatable wings.

13.   Now scientists are testing a lensing technique for studying the quasars themselves.

14.   Scientists are now testing drugs that imitate the terrapinous talent.

15.   Scientists have been testing such an experimental immunization on hundreds of people.

16.   Scientists are testing edible vaccines in which people would be protected from diseases by eating genetically engineered foods.

17.   Scientists have extensively tested one of these remedies, the Vitamin C, and dispute whether it helps, but Bradford and others are unswayed.

18.   Scientists tested the noise sensors last year on whales near the mouth of the Mississippi River.

19.   Several times scientists tested the effects of dumping iron in the water.

20.   Soviet scientists tested nuclear weapons during and after World War II near Semipalatinsk, a desert region in what is now the independent nation of Kazakstan.