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

drop back • drop behind
drop back —
1
. fail to maintain one’s position; be outstripped:
The early leaders drop back and allow others to make the run-
ning. 2. go down; decrease : The unemployment figures
dropped back last month.
drop behind —
1
. = drop back 
1
: Don’t drop behind now, just
when you’re doing so well. 2. fail to maintain a schedule of
payments, etc.: If your payments of rent drop behind, you
will be asked to leave.
See also: back drop / backdrop.
drop dead • drop-dead
drop dead —(sl.) is used as an exclamation of annoyance di-
rected at a person: When Tim’s wife heard this she said: “Tell
him to just drop dead!”
drop-dead —(sl.) extremely; in a spectacular way: Thank
you so much Garcelle for being so drop-dead beautiful, lovely,
and talented.
drop down • fall down
drop down —
1
. come down suddenly: I heard a noise from
the well and saw that the cat had dropped down. 2. bend
downwards; sink down: When they saw the pursuers they
dropped down to take cover. 3. (coll.) pay an unexpected
visit: Let’s drop down to his summer home and see if he’s
there.
fall down —
1
. = drop down 
1
: The hunter fired and the deer
fell down dead. 2. (of a building, etc.) collapse: The steel scaf-
folding fell down and narrowly missed a couple of bystanders.
3. (of a project, etc.) be unsuccessful; fail: His plan fell down
when it proved too costly.
drop from the skies • fall to the ground
drop from the skies —(also: drop from heaven) appear unex-
pectedly as if by magic: “Good gracious, miss,” I said, still
doubting my senses, “have you dropped from the skies?”
fall to the ground —(of plans, etc.) fail; come to nothing: The
whole scheme fell to the ground, although all the details were
thought out.
See also: come down to earth / go to earth.