I think this talk is worth listening to.句中为什么要加to?

I think this talk is worth listening to.句中为什么要加to? This is what I think. I think this TV s____ is boring I think this skirt is too (e ). I think this is against the____(法律). I think this box is made of( ) i think.this is what 改成复合句 This is what I think.什么句式 I think this a( ) is right. i think this life is overrated. I think this is very important for us to have a talk with him .那个错了为什么这么改啊! I think this programme is boring的同义句I ______ think this programme is ______ this is what i think 还是this is how i think.哪个才是对的? I think this is right.(改为否定句) I __ think this __ right. Think and talk with your partner.why is this your favourite festival? I think this film is too_____.I am_____with it.(bore) i think being a reporter is _____.I like to meetpeople and talk with them. 改错i think this is a good book.i don't think iti think this is a good book.i don't think it有什么错?改错