unsure的反義詞是什么

　　例句：

　　There were a lot of things I was unsure about.

　　有許多事情我沒把握。

　　He was unsure of what to do next.

　　他對下一步該做什么猶豫不定。

　　Unsure of the meaning of this remark, Ryle chose to remain silent

　　由于不確定這句話究竟是什么意思，賴爾選擇了保持沉默。