—Look at the sky! What is it?—Oh! UFO is landing on the ground.A. AB. AnC. /D. The

—Look at the sky! What is it?
—Oh! UFO is landing on the ground.
A. A
B. An
C. /
D. The

(答案→)A. AB. AnC. /D. The解析：根据语境可做ＵＦＯ是泛指，故用不定冠词，又因ＵＦＯ的首音素是辅音因素，故用Ａ，故选Ａ。

我也是这个答案