to use anywhere, anytime (card, ticket etc); to be used by everyone (language, textbook etc); (of two or more things) interchangeable
to go through; to know well; (suffix) expert; to connect; to communicate; open; to clear; classifier for letters, telegrams, phone calls etc
to use; to employ; to have to; to eat or drink; expense or outlay; usefulness; hence; therefore
英语是国际通用的语言。
Practice each character