Pentasulfide
五硫化物
🗣️ 情景例句
What classes are mandatory for your major?
你的专业什么课是必修的？
We're in competition with several other companies for the contract.
我们与另外几家公司逐争取这个合同。
I regretted saying it almost at once.
但马上又后悔说了这话。