11．It is easy to show that intelligence is to some extent something we are born ______.

11．It is easy to show that intelligence is to some extent something we are born ______.
A．about B．of C．to D．with
12．______ evidence shows,for example,that people who lived over three thousand years ago ate salted fish.
A．Ancient B．Historic C．Historical D．Old
13．Without trees our world ______ a much drier place.
A．is B．will be C．would be D．must be
14．There are two computers in the office,but ______ is working.
A．either of them B．neither of them C．none of them D．neither of which
15． Americans eat ______ as they actually need every day.
A．twice as much protein B．twice protein as much twice
C．twice protein as much D．protein as twice much