题目

Authorities in Shanghai said Thursday night that another person has died from H7N9 bird flu, bringing the death toll to five around the country. The city has reported six infections (感染) to date, and four have died, said the Shanghai Municipal Health and Family Planning Commission. Of the rest two, there was a four-year-old, the agency said. The baby was recovering from mild illness, it added. The person died at Huashan Hospital on Wednesday and was confirmed infected with the H7N9 bird flu on Thursday. Also on Thursday, the commission reported the city's third death from the H7N9 bird f下列各种说法中，正确的是A. 风筝是靠空气的浮力上升的B. 水下的潜水艇，下潜越深受到的浮力越大C. 气象探测气球里所充气体的密度小于空气密度D. 同一支密度计漂浮在不同液体中，受到的浮力大小不同 C 【解析】解答：A. 风筝是利用流体压强产生的升力升空的，所以该选项不正确。B. 水下的潜水艇，下潜过程中排开水的密度不变，排开液体的体积不变，因此所受浮力保持不变，所以该选项不正确。C. 气象探测气球里所充气体的密度小于空气密度，气球受浮力作用而上升，所以该选项正确。D. 同一支密度计漂浮在不同液体中总处于漂浮状态，所受浮力大小不变，所以该选项不正确。 故选C.