The principles of general mathematics haven't changed in nine hundred years, but everything else has.

The principle of a language lab essentially has not changed.

The basic principle of supply has not changed much over time.

"We are sitting round the table talking about some quite difficult issues, but the principles haven't changed," the spokeswoman said.

Details have been added, but the principle has never changed.

Over the past 200 years or so, the principles of modern advertising haven't changed much.

The linen was (sometimes and in principle) changed every month.

The principles are constant and do not change under new administrations.

Their policies and principles haven't changed, say many centrist Democrats.

The principle never changes: we should do whatever is needed to guarantee absolute respect for human rights.