关于强调句式的问题，英语

强调句可以强调除了谓语部分的其他所有句子成分，当然也可以强调原因。
如：It was because I missed the usual bus that I got late.

需要注意的是，任何强调句，把“it is+that、who”的结构去掉之后，句子仍然完整。如：I got late because I missed the usual bus.
所以1楼的举例有问题，拟改为It is because of your carelessness that this accident happened. (This accident happened because of your carelessness.)

疑问句采用强调句式的比较少见，偶尔选择题当中会碰到，所以要特别谨慎。

我认为可以 举个例子：it is because of your carelessness that lead to this accident.
可以用WHY；why does this accident happen?
或用what:what lead to this accident?
我不是很明白你第二个问题要问啥