电子枪中的阴极向外发射电子的方式不包括()。
A.冷发射
B.一热发射
C.场发射
参考答案:A
The artist spent years on his monumental painting, which covered the whole roof of the church, the biggest in the country.
A.archaic
B.sentimental
C.outstanding
D.entire
使用压缩工具软件,可以将一个“巨型”文件压缩成很小的文件()