invigilate
v[I, Ipr, Tn]
~ (at sth) (Brit) be present during (an examination) to make sure that it is properly conducted, that no cheating occurs, etc (在考场上)监考
invigilate (at) a history exam 监考历史.
My dear friend, Mathilde. Let me tell you something. That necklace you borrowed from me wasn't a real diamond necklace. It wasn't valuable at all. The stones in the necklace were made of glass. It was worth five hundred francs at the most.