be ignorant of

对…不知道(了解)

be fed up, be fed up (with ), be fed up with, be filled with, be fit for, be fond of, be free from, be friends with, be full of, be generous in, be generous with, be glued to, be good at, be good to, be hard of hearing, be hard on sb., be hard pressed to do sth., be hard up, be hard up for money, be harmful to, be in (good) shape, be in charge of, be in despair, be in drink, be in fashion, be in for, be in honour of sb.(sth.), be in love with, be in one's hands, be in sb.'s (sth.'s) honour, be in sympathy with, be in the habit of, be in the wrong, be incapable of, be inferior to, be innocent of..., be interested in, be involved in, be irrelevant to, be jealous of,