【单选题】人们通过观察和研究蜻蜓的飞行特点,发明了直升飞机。这体现了认识的()
【单选题】当传输信道的带宽超过单一信号的带宽时,可以使用( )多路复用技术。
【单选题】(2013·辽宁师范大学附中模拟)Fortunately it happened at night. If the hurricane ________ during the daytime, there ________ more deaths.
A.
had happened; would have been
C.
had happened; would be
D.
happened; would have been
【单选题】Why is Rose given the chance to get on one of the lifeboats?
A.
Because she is from loyal family.
B.
Because she is arranged to marry Cal.
C.
Because she is very rich.
D.
Because of the "women and children first" policy.
【单选题】Why is Rose arranged to marry Cal in the film Titanic?
A.
Because her family has got bankrupted.
B.
Because her mother wants her to marry Cal to stay in the upper class.
C.
Because Rose is spoilt and cannot live without the help of Cal.
D.
Because Rose’s father has arranged the marriage beforehand.
【单选题】当传输信道的带宽超过单一信号的带宽时,可以使用()多路复用技术。
【单选题】当传输信道的带宽超过单一信号的带宽时,可以使用( )多路复用技术。
【简答题】人们通过观察和研究蜻蜓的飞行特点,发明了直升飞机。这体现了认识的()
【简答题】霍夫曼重排反应时,当酰胺的 a 碳有手性,重排后构型____。
【判断题】阵列对象时的距离指的是两个对象之间的净距离。