China’sOlympic110mhurdlesgoldmedalistLiuXiangannouncedh...

問題詳情：

China’s Olympic 110m hurdles gold medalist Liu Xiang announced his retirement ______ the afternoon of April 7th, 2015.

      A. on               B.  in                C. at                          D. since

【回答】

A

知識點：介詞和介詞短語

題型：選擇題