1. What do the underlined words in the following phrases have in common?

To be in the doldrums
To make amends  (used as a noun)
The annals of history
To have the jitters

2. What do the following words and phrases have in common?

MEMOIRS
CHOIR SINGER
FIRST STRING
DOUGLAS FIRS
A FAIR SHAKE
MUSICAL CHAIRS
HIRSUTE

HINT:
2. The title of this puzzle is INTERNALLY YOURS

Answers:

1.  They are plural words without singulars. You can't be in one doldrum, make one amend, review one annal of history, or have one jitter.

2. Hidden in each word or phrase are the initials IRS  (INTERNAL Revenue Service).

Credit: LA Times Crossword
Sylvia Bursztyn and Barry Tunick
INTERNALLY YOURS