Susan stays alone in the classroom and looks sad.()to her?A What happens?B What has happened?C What is happening?D What was happening?该选哪个啊,麻烦加以解释,

Susan stays alone in the classroom and looks sad.()to her?A What happens?B What has happened?C What is happening?D What was happening?该选哪个啊,麻烦加以解释,
Susan stays alone in the classroom and looks sad.()to her?
A What happens?B What has happened?
C What is happening?D What was happening?
该选哪个啊,麻烦加以解释,

Susan stays alone in the classroom and looks sad.()to her?A What happens?B What has happened?C What is happening?D What was happening?该选哪个啊,麻烦加以解释,
B.上句用的是一般现在时,"发生"了什么的动作发生在她看起来伤心之前,并造成了她现在她伤心的这种影响,所以选第二个.

B What has happened? 已经发生了什么，才导致不高兴

B
susan已经发生了一些事情才会不开心 所以选择B