题目

Spending as little as $ 5 a day on someone else could significantly（较大地） boost happiness, the team at the University of British Columbia found. Their experiments on more than 630 Americans showed they were measurably happier when they spent money on others—even if they thought spending the money on themselves would make them happier.  “We wanted to test our theory that how people spend their money is at least as important as how much money they earn，” said Elizabeth Dunn，a psychologist at the University of British Columbia. They asked their 600 volunteers first to ra第二次鸦片战争前后，俄国侵占中国北方领土________平方公里。