读“中国略图”，完成下列问题．
31100 写成小数是0.31。
Mr. Liu is a ____. He works in Bao'an People's Hospital. His house is ____ from the hospital. So he goes to work by ____.He is ____. He helps lots of sick people. He likes his ____.
用电器是将电能转化为其他形式能的器件，在下列用电器中，利用电能转化为机械能的是
的方程
，给出下列四个命题：
，使得方程恰有2个不同实根；②存在实数