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

She for the professor who was ill. [ ]

I have no idea ______ measures the governmentwill take to stop the river from being further polluted.

My mother was seriously ill last month. Luckily, she managed to _________.

The government is asked to _________ a new policy to solve the problem.