You're completely mistaken about Jane.

　　你對(duì)簡(jiǎn)的看法完全錯(cuò)了。

　　He's ignorant about modern technology.

　　他對(duì)現(xiàn)代科技一無(wú)所知。

　　It costs about $10.

　　這大約要花10元錢(qián)。