More and more people have realized that we won’t have cleaner water to drink unless something _______soon.

A．is done

B．was done

C．will be done

D．to be done

对诊断肥厚型梗阻性心肌病最有意义的是

A．心电图出现深而宽的病理性Q波

B．胸骨左缘第三、四肋间有响亮的收缩期杂音

C．用力时心前区闷痛及晕厥史

D．超声心动图发现舒张期室间隔与左室后壁厚度之比≥1.3，伴二尖瓣前叶收缩期向前运动

E．可闻及第三心音及第四心音