Parents are concerned that children who have trouble in school will 'fall through the cracks' in the school system. [=will not be given the help they need; will graduate without anyone noticing that they are unable to do the work]
The program is meant to help workers who may have 'slipped through the cracks' [=who may have not been included in other programs] because of their age.
You ought to 'get cracking' [='get going; get moving'] on that assignment. [=you should start working on that assignment right away]
(..) Thank you, Dennis. Here you go, Sir. It sounded like there were slide bolts on the outside of our doors. See if you can move the lock through the crack in the door. "Unable to connect to the internet" Stay calm, we're getting out of here. We're gonna get Casey. You can do this, Marcia. (..)2016 Split