肺动脉瓣狭窄的心腔改变为
A.右心房扩大B.左心房、右心室扩大C.左心室扩大D.右心室扩大E.左心房、左心室扩大
参考答案:D
I haven’t seen Sara since she was a little girl and she has changed beyond _____.
A.measure
B.strength
C.attitude
D.recognition
某同学利用如图所示装置探究人体吸入的空气和呼出的气体有何不同.回答:
(1)在A处吹气,现象是______;
(2)在A吸气20秒,此时______(填“呼出气”或“空气”)从B端进入石灰水,结果石灰水中没有明显现象;再在B处吹气20秒,石灰水明显变浑浊.据此判断:在空气和呼出气中,二氧化碳的含量哪个大?