first thing first这种说法正确吗?正确的话

first thing first thing first这种说法正确吗?正确的话 the first thing the first thing is像这种句子后加什么形式?属于什么从句?我是说 the first thing is to do还是doing？为什么？I found it difficult______(remember)now.为什么不是I found it is difficult…… 有谁知道first thing first这句话是什么意思?first thing first first first first first first first first “first First First first first first