When it ______ research into heart disease and its effects on the body, we do not have adequate substitutes for the use of animals.

Prof. Richard was crazy about his research. His illness_________ his many years of hard work and irregular diet.

Kitty is talented___________music but I am good_________sports.

The _______ price will save you one dollarfor each dozen.

If the Browns go to visit the Summer Palace， ______ if it ______ rain tomorrow.