full of hope and confidence, or giving cause for hope and confidence

a positive attitude 乐观的态度

On a more positive note, we're seeing signs that the housing market is picking up. 更乐观地说，我们看到了房地产市场正在好转的迹象。

The past ten years have seen some very positive developments in East-West relations. 在过去的10年中东西方关系有了一些非常积极的发展。

There was a very positive response to our new design - people seemed very pleased with it. 我们的新设计得到了非常积极的回应——看来人们对该产品非常满意。

Opposite: negative (WITHOUT HOPE)

certain and without any doubt

[ + (that) ] Are you positive (that) you saw me switch the iron off? 你肯定你看到我关掉了熨斗的开关吗？

"Are you sure it's okay for me to use your mother's car?" "Positive." “你肯定我可以开你母亲的车？”“完全肯定。”

"It was him - I saw him take it." "Are you positive about that?" “是他——我看到他拿的。”“你对此肯定吗？”

(of a test) showing that an illness, condition, drug, chemical, etc. is present

a positive pregnancy test 呈阳性的妊娠检测

She learned the next day that the test was positive, and her doctor prescribed antibiotics.

Opposite: negative (TEST RESULT)

(used to add force to an expression) complete

Far from being a nuisance, she was a positive joy to have around. 有她在身边完全是个乐趣，一点儿都不令人讨厌。

(of a number or amount) more than zero

Two is a positive number. 2是正数。

Opposite: negative (BELOW ZERO)

being the type of electrical charge that is carried by protons

Opposite: negative (ELECTRICITY)

having the rhesus factor in the blood

My blood type is O positive. 我的血型是 O 型 Rh 因子呈阳性。