问题
选择题
The question that puzzles them is ___they can finish the work on time.
A．what it is that
B．what is it that
C．how is it that
D．how it is that
答案
答案：D
题目分析：句意：困扰他们的问题是他们究竟怎样才能按时完成工作。此处is之后是表语从句，表语从句由强调句型构成，相当于：it is how that they can finish the work on time.这里how是连词置于句首。故选D。
