confident and sure of oneself
自信 (zìxìn)
"She walked into the room looking calm and self-assured."
"她走进房间，看起来冷静且自信。" (Tā zǒu jìn fángjiān, kàn qǐlái lěngjìng qiě zìxìn.)
Very old or ancient
a complex problem that may cause more trouble once started
to make a noticeable difference or impact
to gain knowledge through practical experience
to be extremely frightened
to have a very bad memory
