A dictionary of Confusable Phrases: More Than 10,000 Idioms and Collocations

catch someone up in something • catch someone
up on something
catch someone up in something —deeply involve a person in
smth.; wholly occupy smb.’s attention: The accident caught
us all up in the resultant confusion.
catch someone up on something —(coll.) tell a person the news
of smth.: Oh, please catch me up on what your family is doing.
catch someone’s eye • catch someone’s look
catch someone’s eye —attract a person’s attention: I tried to
catch her eye, but she was too engrossed in the book to no-
tice.
catch someone’s look —notice smb.’s glance: Howard laughed
then stopped as he caught her look of disapproval.
catch up on someone • catch up with someone
catch up on someone —
1
. overtake and overcome a person:
The police caught up on the men just as they entered a dark
archway. 2. have a marked effect on smb.: I think his past is
beginning to catch up on him. 3. (coll.) learn the news of a
person: I’ve had a visit from my friend John, and it was nice
to catch up on him.
catch up with someone —
1
. get level with a person when one
has been left behind: Walk on ahead of me. I’ll catch up with
you. 2. = catch up on someone 2: Jet lag caught up with Joe and
he slept for fourteen hours. 3. reach the same stage as smb.
after lagging behind: He’s working hard to catch up with the
others. 4. make a person accountable for past deeds: Gronevelt
felt that the FBI would catch up with them sooner or later. 5.
(coll.) meet with smb. for a casual chat: “And what have you
been up to?” “Nothing much. Catching up with a few people
here.”
catch up on something • catch up with something
catch up on something —do unfinished work; do things that
one has not had time to do until now: Confined to his bed for
a whole week, Smith passed the time catching up on his read-
ing.
catch up with something —(also: catch up to something ) 
1
.
overtake a bus, etc. by walking fast: Jane caught up with the
bus that had almost left her behind. 2. keep pace with smth.:
The fate of Africa depends upon economic advance catching
up with political advance.