[单项选择]关于小区热力站的说法正确的是( )。
A. 设置在单幢建筑物的地沟入口、地下室或底层，向该用户供应热能
B. 多为单独建筑物，向多幢建筑分配热能
C. 用于特大型供热网路，设置在供热主干线和分支干线的连接处
D. 以上三条均不正确

{{B}} Screen Test{{/B}}
1. Every year millions of women are screened with X-rays to pick up signs of breast cancer. If this happens early enough, the disease can often be treated successfully. According to a survey published last year, 21 countries have screening programmes. Nine of them, including Australia, Canada, the US and Spain, screen women under 50.
2. But the medical benefits of screening these younger women are controversial, partly because the radiation brings a small risk of inducing cancer. Also, younger women must be given higher doses of X-rays because their breast tissue is denser.
3. Researchers at the Polytechnic University of Valencia analysed the effect of screening more than 160, 000 women at 11 local clinics. After estimating the women’s cumulative dose o