（2016高考训练）阅读下列材料，从每题所给的选项中选出最佳选项。
SHANGHAI—Health experts in Shanghai are calling for more protection for young children as the latest research shows about half of the youngsters are suffering from secondhand smoke.About 45 percent of children suffer passive smoking in families，50 percent in public places，and almost 6 percent on public transportation，shows a research released by the Shanghai Children's Medical Center on Tuesday.
