单项选择题

In Mr. Allen’s high school class, all the students have to "get married". However, the wedding ceremonies are not real ones but imitations. These mock (模拟的) ceremonies sometimes become so noisy that the loud laughter drowns out the voice of the "minister". Even the two students getting married often begin to giggle (咯咯笑).
The teacher, Mr. Allen, believes that marriage is a difficult and serious business. He wants young people to understand that there are many changes that must take place after marriage. He believes that the need for these psychological and financial adjustments should be understood before people marry.
Mr. Allen doesn’t only introduce his students to major problems faced in marriage such as illness or unemployment. He also exposes them to the nitty-gritty (木质) problems they will face every day. He wants to introduce young people to all trials and tribulations (磨难) that can destroy a marriage to the breaking point. He even familiarizes his students with the problems of divorce and the fact that divorced men must pay child support money for their children and sometimes pay monthly alimony (生活费) to their wives.
What subjects does Mr. Allen introduce to his students