The place (where/ that)?we will have our picnic is not decid

1、第一个填 where,如果选that的话必须前面加上in,in that =where
2、当先行词是place 的时候whare 和in that 可以省略,这个句子应该为this is the right place (in that或者where) he was born.括号里面为省略内容,所以句末不用介词in.