He couldn’t take part in the final exam his serious illness.
A. because
B. lead to
C. because of
D. when
网友回答
A. because
B. lead to
(答案→)C. because of
D. when
解析：考查短语用法。AD项后面要接句子。BC项后面要接名词或者名词短语。Lead to导致，通向；Because of因为，由于；句意：由于严重的疾病，他不能参加最后的考试。故C正确。