In both cases the operations could last from a week to several months.

This operation did not last more than four and twenty hours.

Most military experts still expect that the operation will last at least two weeks, and perhaps six or more.

The operation, which took a week of planning, lasted 90 minutes.

This operation lasted only four hours, from 9 am to 1 pm.

Those operations lasted until the beginning of the second week in January 1951.

The operation began at about 4:00am on 31 July and lasted for a few hours.

The fire then became a defensive operation lasting for several hours.

I treated two people a day, with operations lasting six to eight hours.

According to them, the clean-up operation would last 12 years.