【正确答案】:
LITTLE BY LITTLE A TRACE OF SMILE APPEARED AT THE CORNER OF HER MOUTH, WHILE HER FACE BECAME WHITER AND PLUMPER. 
【题目解析】:本题可从词义的选择入手。原文中的白胖了,并不是字面意义真的肥胖了,而是更圆润丰满了,所以选用plump。现在的白胖也是跟以前作对比,所以应该用比较级形式“whiter and plumper”。Little by little a trace of smile appeared at the corner of her mouth, while her face became whiter and plumper.