触点式信号发生器的触点应安装在().
A.清管球外壁上
B.清管球内壁上
C.清管球内
D.输气管线上
参考答案:D
20世纪70年代,在世界新发现的大油田中,海上油田有31个,约占51.7%,在新增加的地质储量中,海洋占42%,海上钻井平台总数为7021座,其中美国有1079座,委内瑞拉有5033座,苏联有840座。1977年,近海油田有500个,产量4.6亿吨,占世界总产量的15.6%。
20世纪70年代非近海油田数可能是()。
A.多于500个
B.少于500个
C.等于500个
D.不能确定
Soon, more of the information we receive via the Internet could come (6) in digital wrappers. Wrappers are made up (7) software code that’s targeted to do specific things with the data (8) within them, such as helping to define queries for search engines. They also keep (9) from (10) access to that code.
A.insiders
B.money
C.outsiders
D.warehouse