21.   Equally puzzling is why the unidentified signal should switch on genes that make bacteria resistant to antibiotics.

22.   Genes can switch on genes that switch on other genes, allowing for a deceptively large amount of complexity to unfold from a fairly simple recipe.

23.   Geron and associated scientists are working on drugs and gene insertion methods to switch on telomerase in cells.

24.   He flipped down the sunvisor, into which police lights were set, switched on the siren and pulled the Camry over.

25.   Herrera got his out, switched it on ... No dial tone.

26.   Her daughter switched on the television late in the morning, and saw her mother being wheeled out the building on a stretcher.

27.   Home computers are becoming part of the fabric of everyday life, and are increasingly left switched on all the time.

28.   In a second spot, Collinsworth asks Long to switch seats on the studio set with him.

29.   In doing so, the company signalled that it was willing to modify the startup screen consumers would see when they switch on their computer for the first time.

30.   In the glare of headlights, he switched on irrigation pumps and wind machines that spewed out clouds of warming moisture.