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

get caught doing something • get caught up on
something
get caught doing something —be found doing smth. repre-
hensible; get caught in the act: Did Vi get caught driving
without a license? Did she get a ticket?
get caught up on something —do things that one has not had
time to do until now: I have to get caught up on my studies.
I missed two classes.
get cold feet • hotfoot it
get cold feet—lose one’s courage or nerve: Do you think he
is just getting cold feet, or do you think it’s more than that?
We are afraid he just won’t show up at the church.
Note: 
The expression does not correlate in meaning with the
phrase cool one’s heels—(coll.) be kept waiting by smb. in
authority, as for an appointment (also: kick one’s heels): The doc-
tor kept her cooling her heels for almost an hour.
hotfoot it—leave in great haste; walk or run hurriedly: The
camp staff expects that once the shouts of the campers fill the
hollow, the bear will hotfoot it out of there.
Note:
The expression is not equivalent in meaning to the phrase
foot it
—(coll., also: leg it) walk; go on foot: Several of the wagons
became sloughed and the passengers were compelled to “foot
it” to town.
get full marks for something • get full marks in
something
get full marks for something —
1
. gain the maximum number
of marks in a subject: Half the students got full marks for
what was intended to be an easy question. 2. be praised for
some good quality: Mr. Jenkins gets full marks for his courage
and enterprise.
get full marks in something —(also: score full marks in some-
thing ) = get full marks for something 
1
: Only one in six adults
got full marks in a test of six familiar words.