1.positive表示“正的,阳性的”“完全的,纯粹的”时,无比较级和最高级。
2.positive作表语表示“确信的”时,其后可接介词短语、动词不定式或that从句。

用作定语
▲～+n.
 Two is a positive number.二是一个正数。
The positive pole carries a positive charge while the negative pole does a negative charge.正极带正电荷,负极带负电荷。
She is a positive idiot.她完全是个白痴。
用作表语
▲S+be+～
 I am positive.我确信。
The test proved positive.试验结果呈阳性。
▲S+be+～+prep.-phrase
 Can you be positive about what you saw?你能肯定你看得真切吗?
He is positive of it.他肯定这一点。
▲S+be+～+to-v
He is positive to believe in the being of God.他对上帝的存在深信不疑。
She is positive to come.她一定会来。
▲S+be+～+that-clause
I am positive that I saw him.我敢肯定我见过他。

positive, active
参见active条。
positive, actual, real, true
参见actual条。
positive, certain, sure
参见certain条。

［同义词］   actual, certain, hopeful, real, sare
［反义词］   indefinite, negative, uncertain
［词源］＜拉丁语positivus(确实的,静的,正的)