Quadrivalent
a. 四价的\\n[医] 四价的
✅ 同义词
🗣️ 情景例句
A friend in need is a friend indeed.
患难朋友才是真正的朋友。
This problem is hard to solve.
要解决这个问题不简单。
Once, however, it failed to give the correct time.
然而有一次，它却把时间报错。