(~s)
When a new type of drug or medical treatment undergoes ~s, it is tested directly on patients to see if it is effective.
Two rival laser surgery systems are undergoing ~s in the US.
N-COUNT
(~s)
When a new type of drug or medical treatment undergoes ~s, it is tested directly on patients to see if it is effective.
Two rival laser surgery systems are undergoing ~s in the US.
N-COUNT
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012