Theyarealsoaskingparentstokeepaclosewatchontheirchildr...

問題詳情：

 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

知識點：代詞

題型：選擇題