题目

第二节 完形填空 （共20小题，每小题1.5分，满分30分） 阅读下面短文，掌握其大意，然后从36-55各题所给的四个选项(A、B、C和D)中，选出最佳选项。  A philosophy professor stood before his class and had some items in front of him. When class began, 36 he picked up a large 37 jar and began to fill it with rocks 38 to the top, rocks about 2 inches 39 diameter(直径). He then asked the students if the jar was full. They 40 that it was. So the professor then picked up a box of pebbles（鹅卵石） and 41 them into the jar. He shook the jar 42. Th若a＜b，则a-3______b-3，a-4______b-4