To study a foreign language, __________.
D
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General Motors, one of the world's largest auto manufacturers, is expanding its ________ in this country.
When he suddenly ________ up the subject of genetic engineering, there was an embarrassedsilence.
I don't know how we can make ________ on the timetable for any more courses.
Human behavior is mostly a product of learning ________ the behavior of animals dependsmainly on instinct.