The gasoline burned in car engines is the main cause of air pollution in many
cities. In order to reduce pollution, the number of cars on the roads must be reduced.
This is only possible if fewer people drive their cars every day. Thus, if city
governments want to improve the quality of the air in their city, they need to
improve the
a. highway system.
b. quality of life in the city.
c. connections between cities.
d. public transportation system.
34. Imagine a baby about five months old. It can cry and smile, and it can eat and
sleep. Did you know a baby can also count? According to new psychological research, a
small baby can even add and subtract small numbers of objects. People generally think
that these abilities are learned much later, but in fact they are
a. not present until adulthood.
b. learned only by five-month-old babies.
c. already present in small babies.
d. very difficult for children to learn.