制定灭火作战计划是消防队伍()准备工作的一项重要内容。
（A）灭火
（B）训练
（C）执勤
（D）日常
参考答案：A
为测定实验室废液中硫酸的质量分数。小红同学做了如图所示实验，废液中其他成份不与铁粉发生反应。
请计算：
（1）反应后产生的气体的质量是 g。
（2）该废液中硫酸的质量分数。
Network managers have long (140) practical voice-over-IP (VOIP) solutions. VOIP (141) ease network management and decreases costs by converging a company’s telephony and data infrastructures into one network. And a VOIP solution implemented at a company’s head-quarters with far-reaching branch offices can (142) tremendous amounts of (143) in long distance phone bills, provided that solution delivers POTS-like voice (144) over the Internet.
A．frequency
B．length
C．quality
D．quantity
