They are letting us use their puter, and we are giving them the results of our research.
A. in charge
B. in place
C. in return
D. in a row
网友回答
A. in charge
B. in place
(答案→)C. in return
D. in a row
解析：考查短语辨析。句意“他们让我们用他们的电脑，作为回报，我们给他们我们的研究结果。”A“掌管，负责”；B“在原位”；C“作为回报”；D“一排”。故选C。