It is beyond my understanding that many adults ________ be so crazy about Harry Potter series.

He _____ have completed his work; otherwise, he wouldn’t be enjoying himself by the seaside．

To forbid the cheating strictly in this important exam, the authorities have released a rule that students _________ bring any reference books and stationery into their classrooms.

Mr. Smith has promised that all of us will pass the exam, so it ____ so difficult as you imagine.

I chose the most popular major instead of my favorite one，but I had to drop out and started again where I＿＿＿have gone in the first place.