(tōng, ㄊㄨㄥ) to go through; to know well; to connect; to communicate; open [CE-DICT]
過
(か) (pref) (1) surplus- (attaches to start of Sino-Japanese words); excess-; over-; (2) per- (chemical with more of a certain element than found in other compounds of the same constituents) [EDICT]
(guò, ㄍㄨㄛˋ) (experienced action marker); to cross; to go over; to pass (time); to celebrate (a holiday); to live; to get along; excessively; too-; surname Guo [CE-DICT]
來
(lái, ㄌㄞˊ) to come; to arrive; to come round; ever since; next [CE-DICT]