她口角边渐渐的有了笑影，脸上也白胖了。（ ）
A、Little by little the trace of a smile appeared at the corners of her mouth, but her face became whiter and plumper.
B、Little by little the trace of a smile appeared at the corners of her mouth, so her face became whiter and plumper.
C、Little by little the trace of a smile appeared at the corners of her mouth, while her face became whiter and plumper.
D、Little by little the trace of a smile appeared at the corners of her mouth, when her face became whiter and plumper.
【正确答案】：C
【题目解析】：while表示”在...的同时“。
