Undergrounding
(underground 的现在分词) n. 地下, 地铁, 地道, 秘密活动\\na. 地下的, 秘密的\\nadv. 在地下, 秘密地
🗣️ 情景例句
I'm taking 19 credit hours.
我修了十九个学分。
Sorry, I guess I wasn't thinking. I won't do it again.
对不起。我对这事没想过，下次不这样了。
Litter baskets have been placed under the trees, but people still throw their rubbish everywhere.
树下都已设置了废物筐，但是人们仍到处扔垃圾。