Theyarealsoaskingparentstokeepaclosewatchontheirchildr...

问题详情：

 They are also asking parents to keep a close watch on their children, especially during ______ they call the "risky" period: between the middle of the day and sunset.

A. what        B. which     C. that       D. when

【回答】

A

知识点：代词

题型：选择题