His hobby is to collect stamps in his free time.(同义句转换）

His hobby is to collect stamps in his free time.(同义句转换） His hobby is ____(collect) stamps His hobby is (to collect) coins.为什么用to collect? 将show his stamps to us 转换成同义句 Bill will fing work in his free time.（改为同义句） Bill is ___ ___ Jack will find work in his free time.（改为同义句） Jack is going t 同义句转换 He likes singing in his free time Singing i In his free time ,he likes reading.改同义句 In his free time ,he likes reading.同义句 英语. In his free time,he likes reading同义句 in his free time =when__同义句. His hobby is __(collect)stamps请这里应该怎么填,为什么?