问题详情:
It was not until World War II ___ two other scientists managed to use new chemical techniques to purify it.
A. when B. that C. where D. before
【回答】
B知识点:强调句
题型:选择题
问题详情:
It was not until World War II ___ two other scientists managed to use new chemical techniques to purify it.
A. when B. that C. where D. before
【回答】
B知识点:强调句
题型:选择题