Cloning plants is straightforward while cloning animals is _____________ more complicated.

It is difficult for children to change their eating habit later in life. _____，parents should encourage healthy eating from an early age.

I don't think I'm going to Scotland for Christmas, It's such a long way.        ,I haven't got much money left．

____ most children nowadays are the only chidren, they tend to be more self-centered．

Lily seems to know a lot about Hong Kong, but      she has never been there.