6． The problem is______ we haven’t got so many workers．

题目：6． The problem is______ we haven’t got so many workers．

A．which
B．that
C．what
D．why

喵查答案：B

6．B【解析】此题考查表语从句的引导词，四个选项都可以引导表语从句，但表语从句为陈述句时，只能用that引导，故答案为B。