可选择开发区（）等指标来反映开发区用地的开发利用程度。 A.城市建筑密度 B.土地开

数-3.14与-π的大小关系是______．

—Could you tell me ________ tomorrow morning?

—Well, it will start at 9 o'clock. [ ]

A. when the meeting will start

B. when will the meeting start

C. when the meeting started

D. when did the meeting start

人工心脏起搏

钢轨探伤仪电路中，增辉管性能变差，则仪器无扫描基线。37