HEYGOW

Chinese greets the clock more explicitly than English does. 中午好 and 下午好 mark parts of the day that English lumps into "afternoon", and 早 on its own - one syllable, no 好 - is what colleagues actually say to each other in a corridor at nine in the morning. The evening pair is worth learning together: 早点休息 is what you say to someone who should stop working, and 做个好梦 is warmer, for someone you are close to.