【单选题】若配制的溶液需十分精准时,则须用( )量器做容器。
【单选题】As many as ten courses are provided ,and you are free to choose suits you best.
【单选题】An unidentified wit once said, 'laugh, and the world laughs with you. Snore, and you sleep alone. ' Yet snoring is far from a laughing matter, as those unfortunates with good hearing, who are rightly ...
A.
the soft palate and other structures of the throat
B.
the inflowing and outflowing air through the nose
C.
the inflowing and outflowing air through mouth
D.
the vibrations as a result of the inflowing and outflowing air
【单选题】由于内存大小有限,为使得一个或多个作业能在系统中运行,常需要用外存来换取内存。其中以作业为单位对内、外存进行交换的技术称为(8)技术,在作业内部对内、外存进行交换的技术称为(9)技术。用外存换内存是以牺牲程序运行时间为代价的。为提高CPU有效利用率,避免内、外存的频繁交换,(9)技术常用某种(10)来选择换出内存的页面,它的基础是程序的(11)。据此,操作系统可根据(12)来改善系统的性能。(12...
【单选题】You may borrow as many books as you like, provided you show them to ______ is at the desk.
【单选题】若配制的溶液需十分精准时,则须用的量器做容器是
【单选题】(2019 ·文昌高二检测 ) 甲醛分子式为 CH 2 O, 是有强烈刺激性气味的气体 , 甲醛在常温下是气态 , 被世界卫生组织确定为致癌和致畸类物质。下列关于其结构及性质的分析正确的是 ( )
A.
碳原子采取 sp 3 杂化 , 氧原子采取 sp 杂化
B.
甲醛分子中心原子价层电子对数为 4, 含有一对孤电子对 , 是三角锥型结构
C.
甲醛分子与水分子间可以形成氢键 , 甲醛分子间不能形成氢键