无缝线路位移观测桩应预先埋设牢固，或设置在线路两侧的（）上.
参考答案：固定构筑物
Ann was _______ a good mood and kept ______ jokes to us. [ ]
A. in, to tell
B. in, telling
C. on, to tell
D. on, telling
简述计算机硬件组成及各部件的功能。
