1.It is useful to learn a foreign language.(改为同义句)

1.It is useful to learn a foreign language.(改为同义句)
（ ）a foreign language is ( ).
2.When he was young,he often parcticed jumping hard.(同上)
When he was young,he（ ）to work hard at ( ).
3.I like reading animal books most in my spare time.(同上)
（ ）animal books is my favorite( ).
4.Nobody can make him stop playing computer games.(同上)
Nobody can make him （ ） playing computer games.
5.He was able to （tell different shapes of stars in the sky） at the age of nine.（就划线句提问） 因为不能划线,所以我打括号的就是划线句!
（ )was he able to ( ) at the age of nine