Quick study

Gilpatric assumed that his own prior experience would give him an early advantage over McNamara, but this proved erroneous, as McNamara was a quick study and soon got a fix on the management and organization of the Defense Department.

'I mustn't be cracking jokes though, for I've got a part of twelve lengths here, which I must be up in tomorrow night, and I haven't had time to look at it yet; I'm a confounded quick study, that's one comfort.'

... She is a quick study --' 'A what?' 'Learns her part rapidly, I mean. ...

"Ah!" sighs the little widow, "I absolutely don't know how I am! With all this professional jargon, and nothing but 'quick study' and 'lines,' in one ear; and 'left upper' and 'right lower,' in the other, I am almost distracted!"