数据的逻辑结构有线性结构和【 】两大类。
参考答案：非线性结构
解析：数据的逻辑结构有线性结构和非线性结构两大类。
Most of the students felt rather disappointed at the English party. They say that it ______ better organized.
A．had been
B．had to be
C．must have been
D．could have been
预应力混凝土轨道板不允许开裂。普通混凝土框架板及底座混凝土裂缝限值不得大于（）。
A.0.1mm
B.0.2mm
C.0.3mm
D.0.4mm
