⑤ catch up on

[keannu]

The answer is 5, but doesn't "catch up with" make sense here? What is the difference? Is "catch up with" only for speed or physical things, while "catch up on" is for a project or class?
My son david was unable to attend your class yesterday due to a high fever. I'd appreciate it if you understand the situation and help him _________ the class. ① come up with ② deal with ③ catch up with ④ be similar to ⑤ catch up on

 

[Matthew Wai]

The usages are 'catch up on something' and 'catch up with somebody', according to http://www.oxfordlearnersdictionaries.com/definition/english/catch_1#catch_1__312

Not a teacher.

 

[tzfujimino]

I'd choose 'catch up with', because 'the class' refers to a group of students.
'... help him catch up on what he missed' or '... help him catch up on what they(=the other students) did', for instance, would be fine.

 

[Matthew Wai]

'The class' may refer to 'the missed class', so 'catch up on the class' should also be possible.

Not a teacher.

 

[Louiesaha]

......help him to catch up on the class. Just a thought.

not a teacher

 

[Matthew Wai]

'"To" is optional after "help", and I think it's to not use it. In this type of sentence, native speakers more often choose to not use "to" after "help".'── quoted from https://www.usingenglish.com/forum/threads/104737-are-these-sentence-correct?p=516891#post516891

Not a teacher.