promoted left resulting appliancesbenefitedpaying average couples gains commonreflecting founddistribution impatience profitIn the U.S., John Robinson, professor of sociology at the University of Maryland, and Geoffrey Godbey, professor of leisure studies at Penn State University 1 that, since the mid-1960s, the average American had gained five hours a week in free time — that is, time 2 after working, sleeping, commuting, caring for children and doing the chores.The 3 , however, were unevenly distributed. The people who 4 the most were singles and empty-nesters. Those who gained the least — less than an hour — were working 5 with pre-school children, perhaps 6 the trend for parents to spend more time nurturing their offspring.There is, of course, a gender issue here, too. Advances in household 7 may have encouraged women to take 8 jobs: but as we have already noted, technology did not end household chores. As a result, we see appalling inequalities in the 9 of free time between the sexes. According to the Henley Centre, working fathers in the U. 10 48 hours of free time a week. Working mothers get 14.
创建表约束的方法有3种,第一种是在新建表时,在__1__之后创建约束;第二种是在新建表时,在__2__之后创建约束;第三种是表已经存在,可以通过__3__添加约束。