今年是祖国的六十周年华诞，下面是一首《祖国颂》的长诗节选。读后仿照相应的句子，把

     Canada's wealth comes from the exploitation of its rich natural resources and from the work of its
citizens. Canadians are employed in a variety of jobs. All of these jobs can be grouped into one of three
categories: extractive industries, manufacturing industries and service industries.
     Industries that take raw materials from the natural environment are called extractive or primary
industries. Canada has a wealth of natural resources. The extractive industries that have been developed
to exploit these natural resources make an important contribution to the wealth of our economy. Without
these extractive industries and the money they bring from other countries, Canada's economy could not
exist in its present form. Yet only a small percentage of Canada's labour force work in extractive
industries. Extractive industries rely on laboursaving machines instead of human labour.
     Manufacturing industries process the products of extractive industries into finished products.
Manufacturing industries transform raw materials into many different forms to be used by consumers or
by other companies. This processing may be done in one or more stages. For example, iron ore is
transformed into steel in factories. This is called primary manufacturing. The steel is then sent to
companies for further processing into cars, mining equipment, machines, nails, and other products-such
as bicycle frames. This is called secondary manufacturing.
     Manufacturing industries are located in many towns and cities across Canada. Companies try to build
their factories in densely populated areas because they want to near the people who buy their products.
If they locate near their customers, then they save money on shipping costs. Manufacturing industries
provide more jobs to Canadians than do extractive industries. Yet the number of people employed in
manufacturing is still small in comparison to the third category, services. As with extractive industries,
manufacturing process use many machines that require relatively few workers.
     Service industries provide services needed by the extractive and manufacturing industries, and by
society in general. Without these services, society could not operate. The majority of Canadian workers
do not produce "goods" in their jobs. Instead, they provide "services" for others. The range of services
is very great and includes such things as retailing, office work, education, health care, communications,
government, transportation, and personal services.
     Service industries in one form or another are spread over the entire country. In every community
there are stores, banks, schools, police forces, and dozens of other services. The majority of service
industries are found in town and cities because services are provided for people and there are many
more people in urban areas.
     Canada's economy depends upon the creation of jobs in all three types of industry.