题目内容：
It can be inferred from paragraph 2 that before the visa regulations were revised, foreign teachers have to
A．sign new contrarts if they Wanted to continue to work B．go through any formalities if they wanted to stay a bit longer
C．visit a neighboring country if they wanted to renew their visas
D．interview a South Korean official if they wanted to apply for work permits
参考答案：
答案解析：