Since the 1990s records ______________ by CDs.
a) were replaced
b) have been replaced
c) have replaced
b)
In 1925, a company in San Francisco made a small change in a can opener that was a significant _____________ on the original design.
a)improvement
b)creation
c)success
a)
There were ______________many large families 50 years ago.
a)so
b)such
so