The big fire in Shanghai, believed to due to the burning of construction materials, caused 58 deaths and destroyed all the belongings of the people there.
A. have occurred
B. occur
C. have been occurring
D. be occurring
网友回答
(答案→)A. have occurred
B. occur
C. have been occurring
D. be occurring
解析：考查固定句型：Sth is believed to do/to have done…据说将要做/已经做了，句意：上海最大的火灾据说是由于焚烧建筑材料造成的，导致58人死亡，毁了那里人们所有的财物。意思应该使用主动态而且是完成时态的不定式。occur是已经发生的动作，用不定式的完成时态；该词的用法只可能用主动语态。因而答案是have occurred！选A。