there --- many trees in front of my house now

题目

there --- many trees in front of my house now
a is
b are
c was
d were
请说明理由好吗?

答案

选b
第一个答案只能表示现在式的单数形式,而题目是复数,是many
第二个答案是现在时的复数形式,固是正确答案
第三个答案是过去式的单数,也不对
第四个答案是过去式的复数形式,但题目中明显表示的时间是now,固不对