Despite the American love affair with the automobile, 27% of the U.S. population regularly rides a bicycle.

keep an eye on…

Dominic: If we keep driving on this road, I think we'll arrive in two hours.

Janice: Yes, but you need to keep an eye on the gas gauge. The tank is almost empty.

Explanation: To keep an eye on something means to watch it carefully, or to pay close attention to it.

traditional remedies

Patient: What can I do to lessen my chronic back pain?

Doctor: We don't think an operation is necessary. Some traditional remedies such as yoga or acupuncture may help to relieve the pain.

Explanation: a traditional remedy is a way of treatment that is part of the culture or history of a society. It is not usually based on hospital care.

During working hours

Dear Lucy:

I can't write personal emails during work hours, but I'll call you after 6:00 and we can arrange to visit the new health club.

Explanation:  during working hours means the basic time of the day when most people are at their jobs.