More than one example necessary to make the students understand this rule clearl

More than one example _______ necessary to make the students understand this rule clearly.
 A. should be      B. is       C. are        D. have been

试题答案

B

many a(许多) + 单数可数名词或more than one(不止一个) + 单数可数名词作主语时，常遵循“语法一致”的原则，即主语是单数，谓语也用单数。