Read the following paragraph and underline the topic sentence. Apart from its heavy demands on time and money, campus love, though its sincerity should not be doubted, may not be able to stand the test of time. It is relatively easy to maintain a stable relationship on campus, but upon graduation when lovers are faced with different choices—further education or job, staying at home or going abroad—they begin to pursue their respective interests. As a result, lovers may go their separate ways. According to a survey conducted by Nanjing University, 13.6% of campus lovers split up within the one or two months before graduation. Also, due to college students’ limited social contacts, the people they develop romantic relationships with are usually their classmates, schoolmates, or friends they get to know in intercollegiate activities. Once they enter society and meet more people, their idea of a good partner may change and they will probably find someone more suitable for themselves. Thus, campus love gradually perishes as time goes by.