你理解錯了。The crwons were bad, not fit well at all.

If the crown model was good, then it is easily to put on without lots of adjustment. However, the crowns I have got were so bad. The dentist had to spend much time to adjust it. Finally the dentist asked me to give a two weeks to adjust it to see it they would settle down. However, after two week, I still didn't feel well with those crowns. So they did second time adjustment. I didn't even know they would charged for that( $250). That is the job they are supposed to do, now it makes look like they do the favor for me.