题目

完形填空A science teacher wants to tell an idea to his students. He takes a large-mouth bottle and________ a few large stones(石头) in it. He then asks the class: “Is the bottle ________ now?” They all answer: “Yes!”The teacher then takes some small stones and puts them into the ________ .The small stones go into the room ________ the big stones. He then asks: “Is it full?” This time ________ students give no answer, but most answer: “Yes!”The teacher then starts to drop some ________ into the bottle. The sand (沙) goes into the room between the small stones. For the _She seemed________ what I said. I had________ it again. A. to understand; to be saying 　　 B. didn’t understand; said C. not to have understood; to say D. to have understood; been said