.

To help today’s customers make a choice, a company in New York _____a video trolley — a supermarket trolley with a video screen to display advertisement and price information.  

A．has invented

B．had invented

C．invents

D．is inventing

外贸实务中，制作单证时，通常首先制作( )。

A．商业发票

B．汇票

C．提单

D．出口货物明细表