they are going to the great wall on satuday 对划线部分提问 on saturday划线
问题描述：
they are going to the great wall on satuday 对划线部分提问 on saturday划线
答
对日期等提问用when
When are they going to the Great Wall?
补充说明：when和what time对时间提问区别
when可以对日期,具体时间提问；但what time一般对具体的时间提问
比方说：
When is our nex game?
Next Monday或者On 5th November就是一个非常好的回复
但是如果问What time is our next game?
3pm就需要回答一个具体的时间了（当然一般还要加上某个日期或者星期了）