(~s)
If you say that something is a ~, you mean that it helps people in a very important way, often in a way that is important to their health.
The cervical smear test is a ~.
N-COUNT
(~s)
If you say that something is a ~, you mean that it helps people in a very important way, often in a way that is important to their health.
The cervical smear test is a ~.
N-COUNT
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012