One day，a teacher was speaking to a group of students about how to (31) their time．He gave an example those students would never forget．
He pulled out a wide jar(罐子) and put it on the table． He also took out several rocks and carefully put them into the jar one at a time． When no more rocks would( 32) inside，he asked，'Is this jar full?'
Everyone in the class shouted，' Yes． 'The teacher replied，'Really?' He pulled out a box of small stones． He dumped some in and ) (33)the jar． The stones went down into the spaces (34) the big rocks． He then asked the group once more，'Is this jar full?'
'Probably not，'one of them answered． 'Good ! 'he replied． He brought out a glass of sand and dumped the sand into the jar and it went into all of the spaces( 35) ． Once more he asked the question，'Is this jar full?'
'No!'the class shouted． Once again he said，'Good! Then he poured a cup of water in (36) the．jar was full． Then he asked，'What is the key point here?'One student put up his hand and said，'The key point here is that even if you are busy，you can (37) plan everything well if you try really hard ! '' No， the speaker replied，'that's not the point． The point is if you don-t put the big rocks In(38) ，your ’ll never get them in． What are the 'big rocks in your (39) ? Time with your loved ones，your education，or your dreams? Remember to put these big rocks in first，or you ’II never get them in (40) ．'
( )31．