患者，女性，63岁，心绞痛病史2年。一天前骑车上桥时又出现胸骨后压榨样疼痛，即原地休息，含服硝酸甘油3片无效，出冷汗，路人将患者送到急诊室。经心电图检查，诊断为急性前壁心肌梗死，转入CCU进行链激酶治疗。

护士指导患者避免排便时用力，患者问及其理由，正确的回答是（）。

A.用力过度引起虚脱反应

B.腹压增加导致呕吐加剧

C.血压陡升导致脑出血

D.氧耗量增加梗死面积扩大

E.血流加速致脑栓塞

He often helps his teachers and classmates, and is good at almost all his subjects.       , he is worthy of the honor of Top Students.

A．What’s more

B．To our surprise

C．However

D．In general