语法填空(共10小题；每小题1. 5分，满分15分)
阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使用括号中词语的正确形式填空，并将答案填写在答卷标号为16-25的相应位置上。
Six days of spring rain had created a wild river      (run) by Nancy Brown’s farm. As she tried to drive her cows to higher ground, she       (slip) and hit her head on a fallen tree trunk. Nancy was badly hurt and could only walk with great      (difficult). The water      (rise). Nancy’s pace got slower and slower. Finally, all she could do was to throw her arm around Lizzie’s neck and try to hang on. About 20 minutes later, Lizzie managed to      (succeed) pull herself and Nancy out of the water and onto a bit of high land.
It took rescuers another two hours to discover Nancy.     helicopter lowered a doctor,   attached Nancy to a life-support lift. They raised her into the helicopter and took her to the school gym,     the Red Cross had set up an emergency shelter.
When the flood subsided two days later, Nancy immediately went back to the highland. Lizzie was gone.     was one of the 19 cows that Nancy lost. “I owe my life     her,” said Nancy sobbingly.