Nobody in the street knew Miss Hilton. While she lived, her front gate was always locked and no one ever saw her 1 or saw 2 go in. So even if you 3, you couldn't feel sorry and 4 that you 5 Miss Hilton.

    When I think of 6, I see just two colours, grey and green. The green of mango tree, the grey of the house and the grey of the high iron fence（铁栅栏） that kept you off the mangoes.

    If your football 7 Miss Hilton's garden, you never 8. It wasn't the mango season 9 Miss Hilton died. But we got back about ten 10 twelve of our footballs.

    11 the end of the week a sign was shown on the mango tree: For sale.

    We were ready to dislike 12 even before they came. I think we 13. Already we had one man who kept on complaining（抱怨）about us 14 the police. He complained that we played football near his house and if we weren't playing football he complained that we were making 15 noise anyway.

运用“公民的政治生活”知识，简要分析材料中，公民是通过哪些途径参与政治生活的？以及有哪些原则要求？

1948年，美国占资本主义世界工业生产总值比重为54.6%，英国、法国、日本、联邦德国则占19.6%。到1970年，美国所占比重为38%，其他四国为31.5%。这种变化趋势说明的本质问题是（   ）