采用曝气沉砂池，可使沉砂中有机物的含量降至（）以下。

主“决断”是哪一腑的功能？（）

A.胆

B.肾

C.小肠

D.三焦

魏征

He ______ articles for our wall-newspaper these three years, and he ______ about forty articles.

A．has been writing; has written

B．has been writing; wrote

C．is writing; has been writing

D．has written; has written

由一种组元组成的合金成为（）合金。

诊断冠心病最常用的非创伤性检查方法是（）

A.休息时心电图

B.24小时动态心电图

C.心电图运动负荷试验

D.超声心动图

E.心脏CT检查