upgrade

1、upgrade 是两个熟词拼的：up(往上)+ grade(等级、台阶)，往上一档 = 升级。反义直接对着记 downgrade(往下一档)。
2、grade 这一支顺带打包：grade 等级与成绩、graduate 毕业(出自拉丁 gradus「步、台阶」)、progress 前进、gradual 一级一级——都在"一步一台阶"这条线上。
3、词性三种都要会：动词 upgrade your phone 升级；名词 an upgrade 升级后的新版本；名词还有一层老意思"上坡的那段路"，正好和 downgrade(下坡)对着。今天一律写作 upgrade，旧异写 up-grade 已不用。

upgrade (n.)

also up-grade, 1847, "upward slope," from up (adj.) + grade (n.). The meaning "upgraded version" is recorded from 1980.

upgrade (v.)

"increase to a higher grade or rank," 1904 (transitive); 1950 (intransitive), from up (adv.) + grade (v.). Related: Upgraded; upgrading.

1. You can upgrade from self-catering accommodation to a hotel.

您可以将自理膳食旅店升级为酒店。

2. to upgrade the town's leisure facilities

改善镇里的休闲设施

3. We need to upgrade the status of teachers.

我们需要提升老师的地位。

4. So we're going to upgrade you and your friend to first class.

所以我们会将您和您的朋友升等到头等舱.

5. Thefts have been on the upgrade.

盗窃案已在增多.

【update, upgrade, upholder, upset】
update: 更新；
upgrade: 升级，提升；
upholder: 抬高，举起，支持，鼓励，赞同，拥护；
upset: 推翻，颠覆，使不安