Time
Time is tangible. One can gain time, spend time, waste time, save time, or even kill time. Common questions in American English reveal this concrete quality as though time were a possession. “Do you have any time?”, “Can you get some time for this?”, “How much free time do you have?” The treatment of time as a possession influences the way that time is carefully divided.
Generally, Americans are taught to do one thing at a time and may be uncomfortable when an activity is interrupted. In businesses, the careful scheduling of time and the separation of activities are common practices. Appointment calendars are printed with 15-,30-, and 60-minute time slots. The idea that “there is a time and place for everything” extends to American social life. Visitors who drop by without prior notice may interrupt their host’s personal time. Thus, calling friends on the telephone before visiting them is generally preferred to visitors’ dropping by.

Useful words and expressions:
1. tangible 切实的
2. kill time 消磨时间
3. reveal 显示，揭示
4. scheduling 行程安排
5. slot 缝隙
6. drop by 随便访问
7. preferred 首选的