Idiom: "(to) get a handle on"
Definition:
to gain an understanding of
Examples:
1) Calculus is a difficult subject to get a handle on if you don’t study.
2) Once you get a handle on the rules, playing the game is easy.
中文解释：http://www.youzienglish.com/main/idiom_of_the_day/to_get_a_handle_on/cn/
