When we got down to work,a lot of difficulties ______ (arise).请教此空填什么时态,

When we got down to work,a lot of difficulties ______ (arise).请教此空填什么时态,
When we got down to work,a lot of difficulties ______ (arise).请教此空填什么时态,

When we got down to work,a lot of difficulties ______ (arise).请教此空填什么时态,
arose -------- 主过从过.
我们开始工作时,有许多困难.

had arisen
When we got down to work是过去式，后面的是过去的过去，过去已经发生了，所以是过去完成时
有不明白的地方再问哟，祝你学习进步，更上一层楼！ (*^__^*)

arouse，因为前面是过去式，所以后面也用过去式。表示，当我们着手开始工作的时候，一大堆问题出现了。