Semidefinite
[计] 半定的
🗣️ 情景例句
And it hung over Robbie's crib.
Robbie的小床也有过。
When an opportunity is neglected,it never comes back to you.
机不可失，时不再来；机会一过，永不再来。
When might you go?
什么时候想去呢？