下列气体通入水中，气体既作氧化剂又作还原剂的是
A．Cl2
B．NH3
C．SO2
D．CO2
答案：A
37. With the guide _______ the way, we finally got to the village which we were looking for.
A．led
B．leading
C．to lead
D．had led
被少量含气组织覆盖的实质脏器的叩诊音为（）
A.实音
B.清音
C.鼓音
D.过清音
E.浊音
