Prechlorination
预加氯
🗣️ 情景例句
I'm really concerned about them,
我真的为他们担心，
John is not forty-five yet,is he?
约翰不够45岁,是吗？
'I have just arrive in Scotland and I'm staying at a Youth Hostel.'
“我刚到苏格兰，我现住在一家青年招待所。”