long period

How, after so much success over such a long period of time, "a dip"was inevitable.

The biomarkers measured in this test have been developed over a long period and have shown strong performance -- initially in cerebrospinal fluid, then in venous blood samples, and now in blood from superficial vessels in the finger.

Another issue is the process of demining once a conflict is over, and clearing land that has been mined can take a long period of time.

The sequence of building blocks has evolved over a long period of time; we all inherit them from our parents.

The presence of Bes mugs in different contexts over a long period of time made it extremely difficult to speculate on their contents or roles in ancient Egyptian culture.