just like like as的区别
whenever the professor explained something,she kept smiling and nodding her head from time to time （）understanding every word of his lecture.
A.as if B.like C.just like D.as though she
为什么不能选B和C
不是 AS if 后面加句子嘛.问题是现在是动名词形式.不是应该用like嘛