Here are some letter sequences, following a very similar rule. The ordering of the sequences may help you solve the sequences. Good luck!
Y E S _ _ L _ B J _
U D T C C S _ _ _ D
E _ T C _ C S _ N D
P.S.: All errors are intended. Please comment before you edit. Thanks!
P.P.S.: This is my first sequence problem. All constructive feedbacks are welcome.