Question

— Why didn’t they complete the task in time?
— Because it was not until late afternoon _____ they began to solve the major problem．

A．when

B．that

C．before

D．which

Answer 1

B

考查强调句型。此题是一个含有not until 的强调句型，其结构为：it is/was + not until +其它+ that,下一个句子意思为：因为就是在下午晚些时候他们开始解决这个主要的问题。所以选B。