Premium grades
[化] 优等品
🧩 词语组成解析
n. 分数；等级（grade的复数形式）
🗣️ 情景例句
How big is your family?
你家有几口人？
A standard one. Replacement during the first year if all rules for proper use have been followed.
有一个原则，如果在一年内符合各种使用规定，就可更换。
Finding planets is proving hard enough, but finding life on them will prove infinitely more difficult.
寻找行星证明相当困难，但是要在行星上发现生命会变得无比艰难。