告诉

告诉 (gàosu) means 'to tell / to inform' — to convey a piece of information to someone. The defining feature for English speakers is its grammar: 告诉 always takes the listener as a direct object before the content. The pattern is 告诉 + person + content: 我告诉你一件事 ('I'll tell you something'), 他告诉我他要走了 ('he told me he was going to leave'). You cannot say 我告诉一件事 without specifying WHO you're telling.

Compare with English 'I told a story,' which works without naming the listener. The second character 诉 takes a neutral tone in everyday speech (gàosu, not gàosù). Don't confuse 告诉 with 说 (shuō, 'to say / speak'): 说 is about producing speech, while 告诉 is specifically about delivering information to a recipient. For 'don't tell anyone,' the standard form is 别告诉别人 (bié gàosu biérén).