MgO在水泥硬化后才体积膨胀，造成建筑物破坏，所以在水泥原料中完全是有害无益的。
参考答案：错
用动词的适当形式填空
1. a letter from him is a great surprise for me. (receive)
2. How do the awful picture make you ? (feel)
3. Wait before you buy that watch. Let's prices in another store. (compare)
4. Have you read the book by Han Han? ( write)
刺激促胰液素释放的最有效物质是
A．蛋白质分解产物
B．葡萄糖
C．HCl
D．胆酸钠
E．淀粉
