The girl sitting by the window is the only one of the students who from the countryside in our class.
A. was
B. were
C. is
D. are
网友回答
A. was
B. were
(答案→)C. is
D. are
解析：考查定语从句。这个定语从句的先行词是the only one，而不是the students，所以定语从句中用单数形式，在根据上文的is，说明本句使用的是现在时，故C正确。