occupied in／with
busy in／with忙于；从事
They were occupied in building a bridge．他们忙着修建一座桥。
They are mainLy occupied with agriculture．他们主要从事农业。
occur to sb．come to／into sb． 's mind想到
It just occurred to me that we had better make reservations in advance if we
want to see the play this evening．我刚刚想起，如果今晚我们要去看戏，最好预先订座。
It never occurred to him to phone me．他根本没想到要打电话给我。
A new idea suddenly occurred to me．我忽然想到了一个新主意。