填空题 byproduct, substitution, blue chip companies/shares, simplification, franchise, specialization, natural resources, standardization.

填空题 The things we can take from nature.

填空题 Something additional that is produced during a natural or industrial process.

填空题 Something are made easier or less complicated.

填空题 All the things of one particular type are made the same as each other.

填空题 The practice of limiting your interests or activities to one particular subject.

填空题 When someone or something is replaced by someone or something else.

填空题 Permission given by a company to someone who wants to sell its goods or services.

填空题 Companies or shares that make a profit and are considered safe.