21.   The new knowledge is enabling scientists to test their theories and conduct increasingly detailed computer simulations of cosmic history, including the dark age.

22.   The scientists tested few samples and had results that ranged widely.

23.   The scientists did not test for several that have been linked to foreign epidemics or germ warfare.

24.   The scientists tested its effect in obese mice, in normal mice and in a type of mutant mice that develops diabetes.

25.   The scientists tested the compounds against several categories of bacteria, including strains of staphylococcus and streptococcus.

26.   The scientists tested children and adults on their recall of a memorized list of words and numbers.

27.   This week, government scientists tested the technique in a big trailer in the parking lot of the Brentwood Post Office.

28.   To interpret the patterns, scientists are testing hundreds of chemicals with known toxicities to develop a database of genetic signatures against which the unknown compounds can be compared.

29.   To prove that an HIV vaccine is effective, scientists must test it in humans who are exposed to the virus.

30.   To learn whether other body fluids had similar anti-HIV activity, the scientists tested the synovial fluid that lubricates joints and the plasma portion of blood.