【单选题】听力原文:W: What are you going to do this afternoon? M: I told Frank I' d help him work on his car. Q: What did the man plan to do? (16)
A.
To buy Frank a new car.
C.
To help Frank sell his car.
D.
To help Frank repair his car.
【单选题】听力原文:M: Please buy two packs of cigarettes for me while you are at the store. W: I' m not going to any store. I' m going to see Aunt Mary. But I will get them for you at the gas station. Q: Where will...
【单选题】Andy: Are you buying that book on ships? I didn't know you were interested in ships. Betty: I’ m not. I’ve just been looking at the pictures. Look, this is the one I' m buying-on modern aircraft. Andy...
【判断题】连续时间线性定常系统的内部稳定性和外部稳定性是等价的。
【单选题】相同温度、相同摩尔浓度的四种溶液:①CH 3 COONa、②NaHSO 4 、③NaCl、④ 按pH值由大到小的顺序排列,正确的是( )
【单选题】下列关于中断优先级的描述中,( )是不正确的。
A.
80C51每个中断源都有两个中断优先级,即高优先级中断和低优先级中断。
B.
低优先级中断函数在运行过程中可以被高优先级中断所打断。
C.
相同优先级的中断运行时,自然优先级高的中断可以打断自然优先级低的中断。
D.
51单片机复位后IP初值为0,此时默认为全部中断都是低级中断。
【单选题】关于相同温度下物质的量浓度相同的NaCl溶液和NaClO溶液的叙述正确的是
A.
溶液中c(Cl - )等于NaClO溶液中的c(ClO - )与c(HClO)之和
B.
NaCl溶液中离子的总浓度小于NaClO溶液中离子的总浓度
C.
两溶液中的c(H + )与c(OH - )之和相等