At no time and under no circumstances（）the first to use nuclear weapons.

单项选择题（）is known to the world, Mark Twain is a great American writer.

A、 As
B、 That
C、 Who
D、 Which

单项选择题It is high time someone（）Nick that each member of a team has to do his share of work.

A、 could tell
B、 tell
C、 told
D、 would tell