单选题 Educational Service Inc. operates 70 institutes in the United States and they concentrate on providing career-focused degree programs to ______ 28,000 students.
【正确答案】 B
【答案解析】[解析] 副词词义辨析。considerably“相当地，非常”；approximately“大约，近似地”；preferably“更好地，更适宜地”；ideally“理想地”。空后为数字，只有approximately后可接数字。故答案为B。