18. It is generally believed that the chief reason for the increase in population in developed countries is not so much the rise in birth rates as the decline in death rates as a result of the improvement in medical care.
普遍認(rèn)為，在發(fā)達(dá)國家人口增長(zhǎng)的主要原因與其說是出生率的上升，還不如說是由于醫(yī)療保健的改善使死亡率下降了。
19. There is no doubt that the increase in demand caused the rise in prices.
毫無疑問，需求的增長(zhǎng)導(dǎo)致了價(jià)格的上漲。
20. Additional social stresses may also occur because of the population explosion or problems arising from mass migration movements-themselves made relatively easy nowadays by modern means of transport.
由于人口的猛增或大量人口流動(dòng)(現(xiàn)代交通工具使這種流動(dòng)相對(duì)容易)引發(fā)的種種問題也會(huì)對(duì)社會(huì)造成新的壓力。(超循環(huán)背誦大表)
| 北京 | 天津 | 上海 | 江蘇 | 山東 |
| 安徽 | 浙江 | 江西 | 福建 | 深圳 |
| 廣東 | 河北 | 湖南 | 廣西 | 河南 |
| 海南 | 湖北 | 四川 | 重慶 | 云南 |
| 貴州 | 西藏 | 新疆 | 陜西 | 山西 |
| 寧夏 | 甘肅 | 青海 | 遼寧 | 吉林 |
| 黑龍江 | 內(nèi)蒙古 |
