（） the most versatile of the common metals, lead was widely valued and used in ancient times.

单项选择题Mr. Wang and his son, both looking very happy,（）taking a walk in the park.

A. are
B. is
C. has
D. have

单项选择题Spanish people usually speak （） than English people.

A. quick
B. more quick
C. more quickly
D. quicken