【简答题】盼望已久的菏泽高铁正式开建,标志着菏泽进入“高铁时代”。 (1)高铁信息传输系统中使用的光导纤维和电子芯片的关键材料分别为二氧化硅(SiO2)和晶体硅(Si)。将二氧化硅转化为硅的过程属于 (填“物理变化”或“化学变化”)。 (2)高铁列车车体大量使用的镁铝合金属于 (填“金属材料”或“合成材料”),镁铝合金的优点是 。 (3)高铁施工过程中产生的废水、废浆以及机械漏油等,都会对水体产生污染。使用...
【单选题】It is cold today. Take ____________ your jacket and put ____________ your coat. [ ]
【单选题】关于光纤通信,以下说法不正确是( )
C.
它利用了光在一定时间内可以传播大量信息的特点
D.
光导纤维和微波通信及卫星通信一样,都需要建微波中转站
【单选题】维生素B12含量测定需要查阅哪一部药典?
【单选题】—How is your father feeling today? —Much _______. He can’t go to work today.
【单选题】Hardball tactics means to ____________.
A.
be used primarily against powerful negotiators.
B.
clarify the user's adherence to a distributive bargaining approach.
C.
pressure targeted parties to do things they would not otherwise do.
D.
eliminate risk for the person using the tactic.
【简答题】Which of the senses is described hare as being involved in mating?