【题目】Among the biggest problems facing those remote mountainous villages __________the lack of experienced teachers.
A.is
B.are
C.is there
D.are there

【答案】A
【解析】句意：这些偏远山区村庄面临的最大问题之一是有经验老师的缺乏。此句是完全倒装，the lack是句子的主语，一般现在时态，所以答案是A。