Read the following passage and Choose the letter A, B, C or D to indicate the correct answer to each of the questions .
In the USA, there are two days for children to express their love and gratitude to their parents: Mother day and Father's Day.
Mother's Day is celebrated on the second Sunday in May. On this day, mothers usually receive greeting cards and gifts from their husbands and children The best gift of all American moms is a day of leisure. The majority of American mothers have outside jobs as well as housework, so their working days are often very hard. Flowers are an important part of the day. Mothers are often given a plant for the occasion, particularly if they are elderly.
Father's Day is celebrated throughout the USA on the third Sunday in June. The holiday customs are similar to Mother's Day. Dad also receives the same gifts as what moms get on their day.
Question: This passage is mainly about __________.