The current American school calendar was developed in the nineteenth century because of____.
A. the labor demands of the industrial age
B. the growing season on the nation's farms
C. school teachers' demands for more vacation time
D. parents' and children's demand for more time together at home
【C15】
A. faculty
B. quantity
C. quality
D. fragment
【C3】
A. dripping
B. serving
C. diverging
D. clamping
When "product differentiation" is adopted, the product is usually______.
A. advertised as something different from similar products
B. good either for your health or for the environment
C. very profitable for the company
D. environmentally friendly
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