【填句补文】The typical person living alone is neither old nor lonely. ________. The majority of these people have chosen to live alone. They are responding to decreasing social pressure to get married and have a family.
A、This is a dramatic change from the extended families of just a couple of generations ago.
B、The growing number of women with good jobs has done much to increase the number of people living alone.
C、There's more pressure to get married nowadays.
D、In fact, a quarter of the 23 million single people in the U.S. are under the age of 35.
答案解析：空格后句中出现代词“these people”，而空格前句出现的人是单数形式，因此判断空格处应该出现表意复数的人，从而与these people相呼应。而且空格前句提到了“年龄(old)”，所以判断D是答案，a quarter of the 23 million single people是复数名词，而且D中提到了年龄(35岁以下)。
[概括大意]So far there is no data to suggest that people living on metal-rich soils experience a potential health hazard. The levels of metals within naturally contaminated soils are generally not high enough to cause serious health problems. Living on metal-rich soils does not represent a health risk unless large quantities of soil are digested or metal-rich dust is inhaled. However， small children are particularly exposed to metal-rich topsoil in playgrounds and gardens. They are also the most likely ones to eat potentially dangerous metal-rich soil.
The main idea of this paragraph is__________.
A、Potential Hazards of Human Contaminated Soils
B、Research on Channels of Heavy Metals Getting into Human Food Chain
C、Long- term Health Effects on Health Problems
D、No Evidence to Indicate Bad Effects of Naturally Contaminated Soil
答案解析：本段文字涉及到的是自然污染的土壤一般情况下对人体不会造成危害，首句So far there is no data to suggest that people living on metal-rich soils experience a potential health hazard.便提示出这一点，而D选项只是这个句子的同义转述。