题目内容
The scientists hoped further research would lead to a better understanding of the disease, how ______ spread, and what other factors might be involved.
A. they B. it C. one D. which
B
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题目内容
The scientists hoped further research would lead to a better understanding of the disease, how ______ spread, and what other factors might be involved.
A. they B. it C. one D. which
B