Just as the builder is skilled in the handling of his bricks, ______ the experienced writer is skilled in the handling of his words.

A．How to render automobiles pollution-free.
B．How to make smaller and safer automobiles.
C．How to solve the problem of traffic jams.
D．How to develop an automated subway system.

A．keep in the right lane
B．wait to arrive at his destination
C．keep in constant touch with the computer center
D．inform the system of his destination by phone