空间扩散由三种基本类型（）、等级扩散和重新区位扩散。
参考答案：传染扩散
The film was made _________ the soldiers who were devoted to the liberation of our motherland.
[ ]
A .in praise of
B. in celebration of
C. in memory of
D. in search of
操作系统是计算机系统的一种（）。
A. 应用软件
B.通用软件
C. 系统软件
D.工具软件
