单选题 The landscape can change abruptly after a rainstorm in the Great Sahara Desert.
A. quickly B. completely
C. gradually D. slightly

【正确答案】 A
【答案解析】quickly：快速地；sharply：明显地；gradually：逐渐地；slightly：略微地。题中abruptly意为“突然地”，可知A选项符合要求。