锻压时间
参考答案：
点焊时，从焊接电流结束到撤消电极压力之间的一段时间。
Some people think that CD-ROMs will soon be _________ books.
A．as more popular as
B．the most popular than
C．so popular as
D．more popular than
第一届世界博览会集中了（）国家、千余件各类艺术珍品和新机器产品。
A.近20个
B.20余个
C.30多个
