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

 --- How long ____ was this? --- It’s been nearly six years now.

You shouldn’t drive        fast.It’s dangerous.

—What do you think of Zhang Liang Ying's English songs?—Very attractive and lively. Almost no other Super Girls can sing ______ at present, I think.  

First I read the poem to myself and then ________ to the class.