题目

Mr. Clarke works in New York. Last week he brought his family to China. They visited many places of interest and had a good time here. Before they left for Shanghai, the Clarkes climbed up the Great Wall. It was the greatest project about three thousand years ago. They took a lot of _________ there and then they had a picnic under a big tree. Suddenly it _________ to rain and they hurried to the car. And when they returned to the hotel, they couldn’t find the bag. There was an expensive camera in it. They were all _________ it. They could buy another camera_________ had no time to go to the 化简与计算：