I spend 5 minutes to school on foot.

Where would your parents like to live after they retire?– They’d like to live_________.

Start out right away, _____you’ll miss the first train.

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

________ seems to be a strong competition　in China for senior high students to enter college or university.