【单选题】下述哪一项不是活塞式发动机点火系统的功用?
B.
活塞在压缩行程位于上死点前预先确定的角度上点火
【单选题】We know from the text that the author perceives the concept of 'a limitless digital library'(line 1, Paragraph 3)as
【单选题】Choose the word or phrase that is closest in meaning to the underlined part. Earlier we introduced the concept that the identity of an amplitude modulated message signal may under certain circumstance...
A.
may transmit samples that are regular in communications under some conditions
B.
may be in the circumstances that regular message samples are communicated
C.
may be conveyed by sending signal sampled at regular intervals under some conditions
D.
may communicate with certain customers by sending regular samples of the message
【单选题】为充分发挥汽油机性能,其点火提前角一定要调整到使点火时间定在气缸内活塞运动到( )
【单选题】下列说法不正确的是( )
A.
物质的量是一个基本物理量,衡量物质所含微粒集体的多少
B.
1 mol H 2 O的质量等于N A 个H 2 O分子的质量总和(N A 表示阿伏伽德罗常数)
C.
标况下,1 mol任何气体体积约为22.4L
D.
将40g NaOH溶解于500ml水中,所得溶液中NaOH的物质的量浓度为2 mol∕L
【单选题】对语言语音的特征(类似中文中的声母韵母)进行提取建模的模型,称之为( )。
【单选题】The concept that we can turn this around right now is ( ) ridiculous.