One phase of the business cycle is the expan-
sion phase. This phase is a twofold one, including
recovery and prosperity. During the recovery
Line period there is ever-growing expansion of existing
(5) facilities, and new facilities for production are
created. More businesses are created and older
ones expanded. Improvements of various kinds
are made. There is an ever-increasing optimism
about the future of economic growth. Much capi-
(10) tal is invested in machinery or "heavy" industry.
More labor is employed. More raw materials are
required. As one part of the economy develops,
other parts are affected. For example, a great
expansion in automobiles results in an expansion
(15) of the steel, glass, and rubber industries. Roads
are required; thus the cement and machinery
industries are stimulated. Demand for labor and
materials results in greater prosperity for workers
and suppliers of raw materials, including farmers.
(20) This increases purchasing power and the volume
of goods bought and sold. Thus prosperity is dif-
fused among the various segments of the popula-
tion. This prosperity period may continue to rise
and rise without an apparent end. However, a
(25) time comes when this phase reaches a peak and
stops spiralling upwards. This is the end of the
expansion phase.
 

It can be inferred from the passage that the author believes that（）