passage1

题目

passage1
There are three common calendar systems in use by the United States higher education institutions.Semester Systems are one of them.
The academic year is divided into two terms,each of which provides for about 15 weeks of instruction plus a week for final examination.The fall semester,considered the first term of the academic year,usually begins in September or late August,and it is increasingly common for the term to start early enough to be completed before the two-week Chritmas holiday.The second or spring semester usually begins sometime in January and ends in late May or early June.Most schools schedule a one or two-week vacation in March or April.A variation of the semester system being tried by some institutions is the "4-1-4"calendar,which has a four-month fall semester ending in December,a one-month short term in January for which students may enroll if they wish,and another four-month semester beginning early in Februry.
1.In the United States,the students

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