a
The missing letter is T
If you'll note, one letter is missing. The answer is "Missing you" (letter U).
Q
Car trouble and crisis at home are excuses for missing work. They begin with the letter c.
Choir
combo
clutch
Its the second letter in the English alphabet, named for the Greek letter beta. B is also a letter grade below A and above C. It is also a musical note, the chemical symbol for the element boron, and a group of related vitamins (e.g. B1 or thiamine).
Cometscaricaturist
Company
choral
church street five