How do i figure out this christmas worksheet?

So you think you know a lot of Christmas songs? How many of the following songs can you identify by the initials of the first words of the first line of the song? ( For example: OCAYF = O Come All Ye Faithful)

1.)HYAMLC

2.)TFNTADS

3.)GRYMGLNYD

4.)ICUAMC

5.)SNHNAICAIB

6.)OTFDOCMTLGTM

7.)DTHWBOHFLLLLLLLL

8.)YBWOYBNC

9.)JTTWTLHC

10.)YKDADAPAVCACADAB

11.)ISMKSCUTMLN

12.)IDOAWCJLTOIUTK

13.)HTHASGTTNBK

14.)IBTLALLC

15.)OHNTSABS

16.)AIWFCIMTFT

17.)DTTSIAOHOS

18.)WTKOOA

19.)JOSNLYETW