Susan wanted to be independent of her parents. She tried ______alone, but she didn't like it and moved back home. 

A．living

B．tolive

C．tobeliving

D．havinglived

支气管哮喘的表现是（）

A．呼吸性呼吸困难，双肺满布哮鸣音 

B．端坐呼吸，双肺底水泡音 

C．呼吸性呼吸困难，两肺散在干湿啰音 

D．发热，咳嗽，夜间阵发性气急，肺无异常体征 

E．进行性呼吸困难，痰中带血