happen有进行时态但是不可用于被动语态。
例如:It is happening as we speak.(现在进行时)
happen 英[ˈhæpən] 美[ˈhæpən]    
vi. 发生 出现 碰巧 偶然遇到    
[例句]
1、We cannot say for sure what will happen.
我们无法确定会发生什么事。
2、She wondered what would happen if her parents found her. 
她不知道如果父母找到自己会有什么结果。
3、If we had been spotted at that point, I don't know what would have happened to us.
如果当时我们被发现了,我不知道会有什么后果。
4、We happened to discover we had a friend in common.
我们凑巧发现我们有一个共同的朋友。
5、She called Amy to see if she had any idea of her son's whereabouts. As it happened, Amy had. 
她打电话给埃米,看她是否知道自己儿子的行踪。埃米还真就知道。
happen有进行时态吗
happen是动词
所有的时态都可以有
过去时--happened
现在进行时--be happening
一般现在时--happen(s)
一般完成时态--have(has)happened
一般将来时--will happen