问题补充：
“39 Steps”is one of the most exciting films directed by my brother.
A. which were
B. which was
C. that was
D. that were
答案：
A. which were
B. which was
C. that was
(答案→)D. that were
解析：句意：《39级台阶》是最令人兴奋的电影之一，它是被我的哥哥执导的。one of the most exciting films，后接定语从句谓语动词用复数形式，故选D
