The cleanliness classification can be up to grade 7 at the beginning and a year running.

研究表明，建成初期和运转一年后，室内的悬浮粒子和沉降菌指标均达到洁净度国家标准7级。

youdao

Restarting an industrial civilisation might be a lot harder the second time round, because we have used up most of the easily available resources, from oil to high-grade ores.

重新创建一次工业文明要困难得多，因为我们已经用尽了大部分的可用资源，不论是石油还是高级矿石，那时都已经所剩不多。

youdao

In sixth grade, your idea of a friend was the person who went up to Nicky or Susan, your new crush, and asked them to dance with you, so that if they said "no", you wouldn't have to be embarrassed.

六年级时，好朋友是那个走到你喜欢的尼克或苏珊面前，邀请他们与你共舞，即使他们拒绝，也不会让你感到尴尬的人。

youdao

On an intellectual level, we wish that our fcuked up genes might be good enough to make the grade.

FORBES: Egypt Is the Next Tunisia. What Is the Next Egypt?

The second phase involved filtering the waste-water a third time, to bring it up to irrigation grade quality, so that it could be reused locally without upsetting anyone downwind of the plant.

FORBES: Making Rum a Green Enterprise

The solution to this is free trade in crude oil: some portion of US production should be shipped abroad and replaced with crude of a different grade to make up that optimal mixture.

FORBES: Should The US Allow Crude Oil Exports? Obviously, Clearly, Yes