Answer:

INTRO

Answer	Crossword Clue
INTRO	Opening remarks, casually
INTRO	Emcee's line
INTRO	Opening remarks

INTRO	Within, in combinations
INTRO	Mission starter
INTRO	Opening musical passage
INTRO	Emcee's lines
INTRO	Short beginning
INTRO	Emcee's task
INTRO	Low-level course
INTRO	Up-front material

INTRO	First-year course
INTRO	Prefatory words
INTRO	Lead-in
INTRO	Words before Chapter 1
INTRO	Opening passage
INTRO	Freshman's course, briefly
INTRO	Book opener
INTRO	"101" course

INTRO	Emcee's bit
INTRO	Opening
INTRO	Emcee's job
INTRO	Emcee's opening
INTRO	Headliner's cue
INTRO	Opening words
INTRO	"101" class, briefly
INTRO	Brief opening

INTRO	Emcee's responsibility
INTRO	Opening bars
INTRO	Chap. 1 preceder
INTRO	Jazz singer's cue
INTRO	"Heeeeere's Johnny!" is one
INTRO	It may begin with "Here's"
INTRO	Lead-in, briefly
INTRO	"In this corner ..." begins one, briefly

INTRO	Foreword
INTRO	It may begin "And now ..."
INTRO	"SNL" host's monologue, e.g.
INTRO	Foreword, briefly
INTRO	Preamble