1.   Scientists will know more when they start lowering the water level next Tuesday.

2.   Scientists know that cancer may not show up for many years.

3.   Or, does the scientist know first, what he or she is looking for, in order then, to select the information he or she needs.

4.   Although for many years cancer researchers did not believe that viruses caused the disease, scientists now know that several cancers have viral causes.

5.   Also, fewer deer ticks are testing positive for the bacteria that cause Lyme disease, although scientists do not know why.

6.   Also, scientists know very little about what makes some viruses more virulent than others.

7.   Although scientists do not know if the same underlying mechanisms cause these problems in both groups, they believe knowledge and treatments developed for one may help the other.

8.   Although scientists have long known that the universe is expanding, they had assumed that the expansion was gradually slowing because of the gravitational attractions of the galaxies.

9.   Although scientists do not know the source of HIV, the virus that causes AIDS, many suspect it, too, has its origins in Africa.

10.   Although virus levels subside to pretreatment levels, scientists do not know what to make of the HIV-stimulating effect.