Arccosine
反余弦
🗣️ 情景例句
We need to do lots of laundry. Do we have enough detergent?
咱们得洗好多衣服呢。有足够多的洗涤剂吗？
We have 50 provinces.
我们有50个省。
No littering on the campus.
在校园内不准乱丢废物。