题目内容：

阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。

The National Weather Service (NWS) reported that the Tittabawassee River was at least ten 1. (foot) above flood level, and still rising. Under the growing pressure of the water, the Edenville dam and the Sanford dam broke on 19, May, 2020.

The flooding has covered many roads and bridges in Midland County. For 2.( safe) , so far the Michigan National Guard 3.( help) in moving around 11,000 people in the nearby towns of Edenville, Sanford, and Midland from their homes.

Midland is home to the Dow Chemical Company, 4. raises other worries. The company has large chemical tanks in Midland which, if5.(flood),could release(释放)dangerous chemicals into the river.   

For decades, Dow released dangerous chemical pollution into the Tittabawassee River.6.a result, there is an area farther downstream that is7.(heavy) polluted. The chemicals there have settled into the mud on the river bottom and in the areas along the river. The area was supposed8. (clean) up next year. Now there are concerns that the strong flood waters could make the9.(harm) chemicals come out and release them back into the river. This could cause serious problems, and would make any cleanup far 10.difficult.