I can remember very few ____ when he had to cancel his plans because of poor health．

- She got into a(n) _____when she thought she'd forgotten doing homework. 

Living in a big city has many _____, such as good schools, libraries and convenient traffic.

Always read the ________on the bottle carefully and take the right amount of medicine. 

The scientific research on how to protect the rare animals is ________. Many scientists are working hard to find new way to raise the animals by man.