can't query with chinese

[pacost]

hello:

    There is a problem in my use: can't query with chinese.

   evn:

     centos6.10

     redis-5.0.7

    redisearch.so v1.4.19(from :https://github.com/RediSearch/RediSearch/releases/download/v1.4.19/redisearch.so)

    create index :

       

      FT.CREATE myIdx SCHEMA title TEXT body TEXT

    add document to the index:

       

       ft.add myIdx doc15 1 LANGUAGE chinese FIELDS title "中国" body "china-15 is a powerful 国家"


       ft.add myIdx doc16 1 LANGUAGE chinese FIELDS title "中国" body "中国是国家大国"

when i execuitve command:

ft.search myIdx '中国' language chinese
or
ft.search myIdx '@body:中国' language chinese

all return the same result:

1) (integer) 0

in the case, what shall i do?

（My English is very poor, I hope you can understand my problem）