单项选择题A．In San FranciscoB．At an airport. C． At a travel agencyD．In a post office.

单项选择题How many revolutions must the largest cog make in order to bring the cogs back to their original positions

单项选择题BONA FIDE is to genuine as DE FACTO is to________.

单项选择题What letter should replace the question mark

单项选择题Sally had a third again as many as David, who had a third as many again as Francis. Altogether they had 111. How many did David have