If you ask for my opinion, I'd rather that you________for America next week.

A．Concrete and Its Uses
B．Rules for Working with Concrete
C．Concrete, the Homeowner's Joy
D．Concrete, a Test of Character

A．carefulness
B．patience
C．self-control
D．inventiveness

A．The increase of private mail service.
B．A comparison of urban and rural postal services.
C．The development of government postal system.
D．The history of postage stamps.