在低压锅炉锅水中，碱度主要由OH－和CO32－的盐类所组成，在锅内加磷酸盐处理时，还有PO43－的盐类。（）
参考答案：对
读一读，想一想，判断对(√)错(×)。
Hello, I'm Xiaoyong. I'm 8 years old. My favourite colour is red. I have a red bag. My favourite toy is a
ship. It's blue. My favourite friend is Tom. He is a baby now. Haha.
( ) 1. Xiayong is 9 years old.
( ) 2. Xiaoyong's favourite colour is red.
( ) 3. The bag is blue.
( ) 4. Xiaoyong's favourite toy is Tom.
( ) 5. Tom is a baby now.
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