体内钾的主要排出途径是（）
A.肾
B.肺
C.呼吸
D.肝脏
E.肠道
参考答案：A
解析：体内钾的主要排出途径是经肾以尿钾的形式排出。
一新生儿暴发脓毒血症，脓汁标本经涂片革兰染色镜检发现葡萄球菌。试问为确定该菌是否有致病力，应检查哪一种酶（）
A.凝固酶
B.触酶
C.DNA酶
D.尿素酶
E.卵磷脂酶
Which of the following statements best explains the importance of the timing of changes in discretionary fiscal policy Changes in discretionary fiscal policy must be timed properly if they are going to:（）
A. help the government achieve a balanced budget.
B. exert a stabilizing influence on an economy.
C. enable the government to control the money supply.
