CRTSⅠ型轨道板的调整，以基准器为基础，使用三向千斤顶、支撑螺栓、螺纹丝杆顶托等，调整轨道板的（）、方向及（）。
参考答案：高低；凸形挡台缝
In the following essay, each blank has four choices. Choose the best answer and write down on the answer sheet. Spread spectrum simply means that data is sent in small pieces over a number of the (16) frequencies available for use at any time in the specified range. Devices using (17) spread spectrum(DSSS) communicate by (18) each byte of data into several parts and sending them concurrently on different (19) . DSSS uses a lot of the available (20) , about 22 megahertz(MHz).
A．bits
B．frequencies
C．packets
D．messages
群体心理分析主要解决投资者在投资决策过程中产生的心理障碍问题。( )
