Ichnogram
[医] 足印
🗣️ 情景例句
The costs of college get higher every year.
学费逐年增加，越来越贵。
I invited him ti come down, but he wouldn't.
我请他下来，但是他不肯。
Once the oxygen content of the air had risen to 25% it was ready to burn.
一旦氧气在空气中的含量达到25%，它就要燃烧。