(2013·吉林四校高三一诊)I really don't know how to thank you, but for your help, I ________ my lost necklace.

In order to do something meaningful, it’s necessary that you _______ determine what is really important.

In this country it is required that anyone who wants to settle here ______ to pass this kind of test.

It has been announced that candidates ______ remain in their seats until all the papers have been collected. 

. Mr. Green requires that the students ______ cheat in any exam.