1.
have, am trying, want, are celebrating, sounds, am staying, always leave, does the party start, are you coming, am thinking
2.
has always wanted
have you been waiting
have you found
has been asking
I've never tried
has been dancing
has been raining
3.
Samantha rarely invites teachers to her party
Samantha usually has a chocolate birthday cake
Samantha never has clowns at her party
Samantha sometimes throws streamers at her party
Samantha often has her party a month earlier
4.
b, a, c, c, c