Correct the errors in the following sentence.
Tony and Lona saw hundreds of lightning bugs flickering over the lake. While they were taking a midnight walk. They were also attacked by hundreds of man-of-war mosquitoes.
【正确答案】：Tony and Lona saw hundreds of lightning bugs flickering over the lake. While they were taking a midnight walk , they were also attacked by hundreds of man-of-war mosquitoes.
【题目解析】：p55